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Title: Animals of the Past
Author: Frederic A. Lucas
Release Date: November 14, 2011 [EBook #38013]
Language: English
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ANIMALS OF THE PAST
[Illustration: Phororhacos, a Patagonian Giant of the Miocene.
_From a drawing by Charles R. Knight._]
_Science for Everybody_
ANIMALS OF THE PAST
BY FREDERIC A. LUCAS
_Curator of the Division of Comparative Anatomy,
United States National Museum_
FULLY ILLUSTRATED
NEW YORK
McCLURE, PHILLIPS & CO.
1901
COPYRIGHT, 1900, BY S. S. MCCLURE CO.
1901, BY MCCLURE, PHILLIPS & CO.
PUBLISHED NOVEMBER, 1901.
TABLE OF CONTENTS
INTRODUCTORY AND EXPLANATORY
Use of scientific names, xvi; estimates of age of earth, xvii;
restorations by Mr. Knight, xviii; Works of Reference, xix.
I. FOSSILS, AND HOW THEY ARE FORMED
Definition of fossils, 1; fossils may be indications of animals
or plants, 2; casts and impressions, 3; why fossils are not more
abundant, 4; conditions under which fossils are formed, 5;
enemies of bones, 6; Dinosaurs engulfed in quicksand, 8;
formation of fossils, 9; petrified bodies frauds, 10; natural
casts, 10; leaves, 13; incrustations, 14; destruction of
fossils, 15; references, 17.
II. THE EARLIEST KNOWN VERTEBRATES
Methods of interrogating Nature, 18; thickness of sedimentary
rocks, 20; earliest traces of life, 21; early vertebrates
difficult of preservation, 22; armored fishes, 23; abundance of
early fishes, 25; destruction of fish, 26; carboniferous sharks,
29; known mostly from teeth and spines, 30; references, 32.
III. IMPRESSIONS OF THE PAST
Records of extinct animals, 33; earliest traces of animal life,
34; formation of tracks, 35; tracks in all strata, 36; discovery
of tracks, 37; tracks of Dinosaurs, 39; species named from
tracks, 41; footprints aid in determining attitude of animals,
43; tracks at Carson City, 45; references, 47.
IV. RULERS OF THE ANCIENT SEAS
The Mosasaurs, 49; history of the first known Mosasaur, 50; jaws
of reptiles, 53; extinction of Mosasaurs, 55; the sea-serpent,
56; Zeuglodon, 58; its habits, 59; Koch's Hydrarchus, 61; bones
collected by Mr. Schuchert, 63; abundance of sharks, 64; the
great Carcharodon, 65; arrangement of sharks' teeth, 67;
references, 68.
V. BIRDS OF OLD
Earliest birds, 70; wings, 71; study of young animals, 73; the
curious Hoactzin, 74; first intimation of birds, 76;
Archæopteryx, 77; birds with teeth, 78; cretaceous birds, 79;
Hesperornis, 80; loss of power of flight, 81; covering of
Hesperornis, 82; attitude of Hesperornis, 83; curious position
of legs, 84; toothed birds disappointing, 85; early development
of birds, 86; eggs of early birds, 87; references, 88.
VI. THE DINOSAURS
Discovery of Dinosaur remains, 90; nearest relatives of
Dinosaurs, 91; relation of birds to reptiles, 92; brain of
Dinosaurs, 93; parallel between Dinosaurs and Marsupials, 95;
the great Brontosaurus, 96; food of Dinosaurs, 97; habits of
Diplodocus, 99; the strange Australian Moloch, 100; combats of
Triceratops, 101; skeleton of Triceratops, 102; Thespesius and
his kin, 104; the carnivorous Ceratosaurus, 106; Stegosaurus,
the plated lizard, 106; preferences, 109.
VII. READING THE RIDDLES OF THE ROCKS
Fossils regarded as sports of nature, 111; qualifications of a
successful collector, 112; chances of collecting, 114;
excavation of fossils, 115; strengthening fossils for shipment,
117; great size of some specimens, 118; the preparation of
fossils, 119; mistakes of anatomists, 120; reconstruction of
Triceratops, 121; distinguishing characters of bones, 122; the
skeleton a problem in mechanics, 124; clothing the bones with
flesh, 127; the covering of animals, 127; outside ornamentation,
129; probabilities in the covering of animals, 130; impressions
of extinct animals, 131; mistaken inferences from bones of
Mammoth, 133; coloring of large land animals, 134; color
markings of young animals, 136; references, 137.
VIII. FEATHERED GIANTS
Legend of the Moa, 139; our knowledge of the Moas, 141; some
Moas wingless, 142; deposits of Moa bones, 143; legend of the
Roc, 144; discovery of Æpyornis, 145; large-sounding names, 146;
eggs of great birds, 147; the Patagonian Phororhacos, 149; the
huge Brontornis, 150; development of giant birds, 153;
distribution of flightless birds, 154; relation between
flightlessness and size, 156; references, 156.
IX. THE ANCESTRY OF THE HORSE
North America in the Eocene age, 160; appearance of early
horses, 163; early domestication of the horse, 165; the toes of
horses, 166; Miocene horses small, 167; evidence of genealogy of
the horse, 170; meaning of abnormalities, 170; changes in the
climate and animals of the West, 174; references, 176.
X. THE MAMMOTH
The story of the killing of the Mammoth, 177; derivation of the
word "mammoth," 178; mistaken ideas as to size of the Mammoth,
179; size of Mammoth and modern elephants, 180; finding of an
entire Mammoth, 182; birthplace of the Mammoth, 184; beliefs
concerning its bones, 185; the range of the animal, 186;
theories concerning the extinction of the Mammoth, 188; Man and
Mammoth, 189; origin of the Alaskan Live Mammoth Story, 190;
traits of the Innuits, 192; an entire Mammoth recently found,
194; references, 195.
XI. THE MASTODON
Differences between Mastodon and Mammoth, 198; affinities of the
Mastodon, 200; vestigial structures, 201; distribution of
American Mastodon, 203; first noticed in North America, 204;
thought to be carnivorous, 206; Koch's Missourium, 208; former
abundance of Mastodons, 209; appearance of the animal, 210; its
size, 211; was man contemporary with Mastodon? 213; the Lenape
stone, 215; legend of the big buffalo, 216; references, 218.
XII. WHY DO ANIMALS BECOME EXTINCT?
Extinction sometimes evolution, 221; over-specialization as a
cause for extinction, 222; extinction sometimes unaccountable,
223; man's capability for harm small in the past, 224; old
theories of great convulsions, 226; changes in nature slow, 227;
the case of Lingula, 228; local extermination, 229; the Moas and
the Great Auk, 232; the case of large animals, 233;
inter-dependence of living beings, 234; coyotes and fruit, 236;
Shaler on the Miocene flora of Europe, 236; man's desire for
knowledge, 238.
INDEX, 243
NOTE ON THE ILLUSTRATIONS
The original drawings, made especially for this book, are by Charles R.
Knight and James M. Gleeson, under the direction of Mr. Knight. The fact
that the originals of these drawings have been presented to and accepted
by the United States National Museum is evidence of their scientific
value. Mr. Knight has been commissioned by the Smithsonian Institution,
the United States National Museum, and the New York Museum of Natural
History, to do their most important pictures of extinct animals. He is
the one modern artist who can picture prehistoric animals with artistic
charm of presentation as well as with full scientific accuracy. In this
instance, the author has personally superintended the artist's work, so
that it is as correct in every respect as present knowledge makes
possible. Of the minor illustrations, some are by Mr. Bruce Horsfall, an
artist attached to the staff of the New York Museum of Natural History,
and all have been drawn with the help of and under the author's
supervision.
LIST OF ILLUSTRATIONS
Fig. Page
Phororhacos, a Patagonian Giant of the Miocene _From a Drawing
by Charles R. Knight_ _Frontispiece_
1. Diplomystus, an Ancient Member of the Shad Family _From the
fish-bed at Green River, Wyoming. From a specimen in the United
States National Museum._ 4
2. Bryozoa, from the Shore of the Devonian Sea that Covered
Eastern New York _From a specimen in Yale University Museum,
prepared by Dr. Beecher._ 10
3. Skeleton of a Radiolarian Very Greatly Enlarged 17
4. Cephalaspis and Loricaria, an Ancient and a Modern Armored
Fish 24
5. Pterichthys, the Wing Fish 32
6. Where a Dinosaur Sat Down 38
7. Footprints of Dinosaurs on the Brownstone of the Connecticut
Valley _From a slab in the museum of Amherst College._ 40
8. The Track of a Three-toed Dinosaur 47
9. A Great Sea Lizard, _Tylosaurus Dyspelor From a drawing by
J. M. Gleeson._ 52
10. Jaw of a Mosasaur, Showing the Joint that Increased the
Swallowing Capacity of that Reptile 54
11. Koch's Hydrarchus. Composed of Portions of the Skeletons of
Several Zeuglodons 62
12. A Tooth of Zeuglodon, One of the "Yoke Teeth," from which it
derives the name 69
13. Archæopteryx, the Earliest Known Bird _From the specimen in
the Berlin Museum._ 70
14. Nature's Four Methods of Making a Wing: Bat, Pteryodactyl,
Archæopteryx, and Modern Bird 72
15. Young Hoactzins 75
16. Hesperornis, the Great Toothed Diver _From a drawing by J.
M. Gleeson._ 82
17. Archæopteryx _As Restored by Mr. Pycraft._ 89
18. Thespesius, a Common Herbivorous Dinosaur of the Cretaceous
_From a drawing by Charles R. Knight._ 90
19. A Hind Leg of the Great Brontosaurus, the Largest of the
Dinosaurs 96
20. A Single Vertebra of Brontosaurus 97
21. Moloch, a Modern Lizard that Surpasses the Stegosaurs in All
but Size _From a drawing by J. M. Gleeson._ 100
22. Skeleton of Triceratops 103
23. The Horned Ceratosaurus, a Carnivorous Dinosaur _From a
drawing by J. M. Gleeson._ 106
24. Stegosaurus, an Armored Dinosaur of the Jurassic _From a
drawing by Charles R. Knight._ 108
25. Skull of Ceratosaurus _From a specimen in the United States
National Museum._ 110
26. Triceratops, He of the Three-horned Face _From a statuette
by Charles R. Knight._ 126
27. A Hint of Buried Treasures 137
28. Relics of the Moa 140
29. Eggs of Feathered Giants, Æpyornis, Ostrich, Moa, Compared
with a Hen's Egg 148
30. Skull of Phororhacos Compared with that of the Race-horse
Lexington 151
31. Leg of a Horse Compared with that of the Giant Moa 152
32. The Three Giants, Phororhacos, Moa, Ostrich 158
33. Skeleton of the Modern Horse and of His Eocene Ancestor 161
34. The Development of the Horse 168
35. The Mammoth _From a drawing by Charles R. Knight._ 176
36. Skeleton of the Mammoth in the Royal Museum of St.
Petersburg 183
37. The Mammoth _As engraved by a Primitive Artist on a Piece of
Mammoth-Tusk._ 196
38. Tooth of Mastodon and of Mammoth 199
39. The Missourium of Koch _From a Tracing of the Figure
Illustrating Koch's Description._ 207
40. The Mastodon _From a drawing by J. M. Gleeson._ 210
41. The Lenape Stone, Reduced 219
_INTRODUCTORY AND EXPLANATORY_
_At the present time the interest in the ancient life of this earth is
greater than ever before, and very considerable sums of money are being
expended to dispatch carefully planned expeditions to various parts of
the world systematically to gather the fossil remains of the animals of
the past. That this interest is not merely confined to a few scientific
men, but is shared by the general public, is shown by the numerous
articles, including many telegrams, in the columns of the daily papers.
The object of this book is to tell some of the interesting facts
concerning a few of the better known or more remarkable of these extinct
inhabitants of the ancient world; also, if possible, to ease the strain
on these venerable animals, caused by stretching them so often beyond
their due proportions._
_The book is admittedly somewhat on the lines of Mr. Hutchinson's
"Extinct Monsters" and "Creatures of Other Days," but it is hoped that
it may be considered with books as with boats, a good plan to build
after a good model. The information scattered through these pages has
been derived from varied sources; some has of necessity been taken from
standard books, a part has been gathered in the course of museum work
and official correspondence; for much, the author is indebted to his
personal friends, and for a part, he is under obligations to friends he
has never met, who have kindly responded to his inquiries. The endeavor
has been conscientiously made to exclude all misinformation; it is,
nevertheless, entirely probable that some mistakes may have crept in,
and due apology for these is hereby made beforehand._
_The author expects to be taken to task for the use of scientific names,
and the reader may perhaps sympathize with the old lady who said that
the discovery of all these strange animals did not surprise her so much
as the fact that anyone should know their names when they were found.
The real trouble is that there are no common names for these animals.
Then, too, people who call for easier names do not stop to reflect
that, in many cases, the scientific names are no harder than others,
simply less familiar, and, when domesticated, they cease to be hard:
witness mammoth, elephant, rhinoceros, giraffe, boa constrictor, all of
which are scientific names. And if, for example, we were to call the
Hyracotherium a Hyrax beast it would not be a name, but a description,
and not a bit more intelligible._
_Again, it is impossible to indicate the period at which these creatures
lived without using the scientific term for it--Jurassic, Eocene,
Pliocene, as the case may be--because there is no other way of doing
it._
_Some readers will doubtless feel disappointed because they are not told
how many years ago these animals lived. The question is often asked--How
long ago did this or that animal live? But when the least estimate puts
the age of the earth at only 10,000,000 years, while the longest makes
it 6,000,000,000, it does seem as if it were hardly worth while to name
any figures. Even when we get well toward the present period we find the
time that has elapsed since the beginning of the Jurassic, when the
Dinosaurs held carnival, variously put at from 15,000,000 to 6,000,000
years; while from the beginning of the Eocene, when the mammals began to
gain the supremacy, until now, the figures vary from 3,000,000 to
5,000,000 years. So the question of age will be left for the reader to
settle to his or her satisfaction._
_The restorations of extinct animals may be considered as giving as
accurate representations of these creatures as it is possible to make;
they were either drawn by Mr. Knight, whose name is guarantee that they
are of the highest quality, or by Mr. Gleeson, with the aid of Mr.
Knight's criticism. That they are infallibly correct is out of the
question; for, as Dr. Woodward writes in the preface to "Extinct
Monsters," "restorations are ever liable to emendation, and the present
... will certainly prove no exception to the rule." As a striking
instance of this, it was found necessary at the last moment to change
the figure of Hesperornis, the original life-like portrait proving to be
incorrect in attitude, a fact that would have long escaped detection but
for the Pan-American Exposition. The connection between the two is
explained on page 76. However, the reader may rest assured that these
restorations are infinitely more nearly correct than many figures of
living animals that have appeared within the last twenty-five years, and
are even now doing duty._
_The endeavor has been made to indicate, at the end of each chapter, the
museums in which the best examples of the animals described may be seen,
and also some book or article in which further information may be
obtained. As this book is intended for the general reader, references to
purely technical articles have, so far as possible, been avoided, and
none in foreign languages mentioned._
_For important works of reference on the subject of paleontology, the
reader may consult "A Manual of Paleontology," by Alleyne Nicholson and
R. Lydekker, a work in two volumes dealing with invertebrates,
vertebrates, and plants, or "A Text-Book of Paleontology," by Karl von
Zittel, English edition, only the first volume of which has so far been
published. An admirable book on the vertebrates is "Outlines of
Vertebrate Paleontology," by Arthur Smith Woodward. It is to be
understood that these are not at all "popular" in their scope, but
intended for students who are already well advanced in the study of
zoölogy._
ANIMALS OF THE PAST I
FOSSILS, AND HOW THEY ARE FORMED
"_How of a thousand snakes each one
Was changed into a coil of stone._"
Fossils are the remains, or even the indications, of animals and plants
that have, through natural agencies, been buried in the earth and
preserved for long periods of time. This may seem a rather meagre
definition, but it is a difficult matter to frame one that will be at
once brief, exact, and comprehensive; fossils are not necessarily the
remains of extinct animals or plants, neither are they, of necessity,
objects that have become petrified or turned into stone.
Bones of the Great Auk and Rytina, which are quite extinct, would hardly
be considered as fossils; while the bones of many species of animals,
still living, would properly come in that category, having long ago been
buried by natural causes and often been changed into stone. And yet it
is not essential for a specimen to have had its animal matter replaced
by some mineral in order that it may be classed as a fossil, for the
Siberian Mammoths, found entombed in ice, are very properly spoken of as
fossils, although the flesh of at least one of these animals was so
fresh that it was eaten. Likewise the mammoth tusks brought to market
are termed fossil-ivory, although differing but little from the tusks of
modern elephants.
Many fossils indeed merit their popular appellation of petrifactions,
because they have been changed into stone by the slow removal of the
animal or vegetable matter present and its replacement by some mineral,
usually silica or some form of lime. But it is necessary to include
'indications of plants or animals' in the above definition because some
of the best fossils may be merely impressions of plants or animals and
no portion of the objects themselves, and yet, as we shall see, some of
our most important information has been gathered from these same
imprints.
Nearly all our knowledge of the plants that flourished in the past is
based on the impressions of their leaves left on the soft mud or smooth
sand that later on hardened into enduring stone. Such, too, are the
trails of creeping and crawling things, casts of the burrows of worms
and the many footprints of the reptiles, great and small, that crept
along the shore or stalked beside the waters of the ancient seas. The
creatures themselves have passed away, their massive bones even are
lost, but the prints of their feet are as plain to-day as when they were
first made.
Many a crustacean, too, is known solely or mostly by the cast of its
shell, the hard parts having completely vanished, and the existence of
birds in some formations is revealed merely by the casts of their eggs;
and these natural casts must be included in the category of fossils.
Impressions of vertebrates may, indeed, be almost as good as actual
skeletons, as in the case of some fishes, where the fine mud in which
they were buried has become changed to a rock, rivalling porcelain in
texture; the bones have either dissolved away or shattered into dust at
the splitting of the rock, but the imprint of each little fin-ray and
every threadlike bone is as clearly defined as it would have been in a
freshly prepared skeleton. So fine, indeed, may have been the mud, and
so quiet for the time being the waters of the ancient sea or lake, that
not only have prints of bones and leaves been found, but those of
feathers and of the skin of some reptiles, and even of such soft and
delicate objects as jelly fishes. But for these we should have little
positive knowledge of the outward appearance of the creatures of the
past, and to them we are occasionally indebted for the solution of some
moot point in their anatomy.
The reader may possibly wonder why it is that fossils are not more
abundant; why, of the vast majority of animals that have dwelt upon the
earth since it became fit for the habitation of living beings, not a
trace remains. This, too, when some objects--the tusks of the Mammoth,
for example--have been sufficiently well preserved to form staple
articles of commerce at the present time, so that the carved handle of
my lady's parasol may have formed part of some animal that flourished at
the very dawn of the human race, and been gazed upon by her
grandfather a thousand times removed. The answer to this query is that,
unless the conditions were such as to preserve at least the hard parts
of any creature from immediate decay, there was small probability of its
becoming fossilized. These conditions are that the objects must be
protected from the air, and, practically, the only way that this happens
in nature is by having them covered with water, or at least buried in
wet ground.
[Illustration: Fig. 1.--Diplomystus, an Ancient Member of the Shad
Family. From the Fishbed at Green River, Wyoming. _From a specimen in
the United States National Museum._]
If an animal dies on dry land, where its bones lie exposed to the
summer's sun and rain and the winter's frost and snow, it does not take
these destructive agencies long to reduce the bones to powder; in the
rare event of a climate devoid of rain, mere changes of temperature, by
producing expansion and contraction, will sooner or later cause a bone
to crack and crumble.
Usually, too, the work of the elements is aided by that of animals and
plants. Every one has seen a dog make way with a pretty good-sized bone,
and the Hyena has still greater capabilities in that line; and ever
since vertebrate life began there have been carnivorous animals of some
kind to play the rôle of bone-destroyers. Even were there no carnivores,
there were probably then, as now, rats and mice a-plenty, and few
suspect the havoc small rodents may play with a bone for the grease it
contains, or merely for the sake of exercising their teeth. Now and then
we come upon a fossil bone, long since turned into stone, on which are
the marks of the little cutting teeth of field mice, put there long,
long ago, and yet looking as fresh as if made only last week. These
little beasts, however, are indirect rather than direct agents in the
destruction of bones by gnawing off the outer layers, and thus
permitting the more ready entrance of air and water. Plants, as a rule,
begin their work after an object has become partly or entirely buried in
the soil, when the tiny rootlets find their way into fissures, and,
expanding as they grow, act like so many little wedges to force it
asunder.
Thus on dry land there is small opportunity for a bone to become a
fossil; but, if a creature so perishes that its body is swept into the
ocean or one of its estuaries, settles to the muddy bottom of a lake or
is caught on the sandy shoals of some river, the chances are good that
its bones will be preserved. They are poorest in the ocean, for unless
the body drifts far out and settles down in quiet waters, the waves
pound the bones to pieces with stones or scour them away with sand,
while marine worms may pierce them with burrows, or echinoderms cut
holes for their habitations; there are more enemies to a bone than one
might imagine.
Suppose, however, that some animal has sunk in the depths of a quiet
lake, where the wash of the waves upon the shore wears the sand or rock
into mud so fine that it floats out into still water and settles there
as gently as dew upon the grass. Little by little the bones are covered
by a deposit that fills every groove and pore, preserving the mark of
every ridge and furrow; and while this may take long, it is merely a
matter of time and favorable circumstance to bury the bones as deeply as
one might wish. Scarce a reader of these lines but at some time has cast
anchor in some quiet pond and pulled it up, thickly covered with sticky
mud, whose existence would hardly be suspected from the sparkling waters
and pebbly shores. If, instead of a lake, our animal had gone to the
bottom of some estuary into which poured a river turbid with mud, the
process of entombment would have been still more rapid, while, had the
creature been engulfed in quicksand, it would have been the quickest
method of all; and just such accidents did take place in the early days
of the earth as well as now. At least two examples of the great Dinosaur
Thespesius have been found with the bones all in place, the thigh bones
still in their sockets and the ossified tendons running along the
backbone as they did in life. This would hardly have happened had not
the body been surrounded and supported so that every part was held in
place and not crushed, and it is difficult to see any better agency for
this than burial in quicksand.
If such an event as we have been supposing took place in a part of the
globe where the land was gradually sinking--and the crust of the earth
is ever rising and falling--the mud and sand would keep on accumulating
until an enormously thick layer was formed. The lime or silica contained
in the water would tend to cement the particles of mud and grains of
sand into a solid mass, while the process would be aided by the pressure
of the overlying sediment, the heat created by this pressure, and that
derived from the earth beneath. During this process the animal matter of
bones or other objects would disappear and its place be taken by lime or
silica, and thus would be formed a layer of rock containing fossils. The
exact manner in which this replacement is effected and in which the
chemical and mechanical changes occur is very far from being definitely
known--especially as the process of "fossilization" must at times have
been very complicated.
In the case of fossil wood greater changes have taken place than in the
fossilization of bone, for there is not merely an infiltration of the
specimen but a complete replacement of the original vegetable by mineral
matter, the interior of the cells being first filled with silica and
their walls replaced later on. So completely and minutely may this
change occur that under the microscope the very cellular structure of
the wood is visible, and as this varies according to the species, it is
possible, by microscopical examination, to determine the relationship of
trees in cases where nothing but fragments of the trunk remain.
The process of fossilization is at best a slow one, and soft substances
such as flesh, or even horn, decay too rapidly for it to take place, so
that all accounts of petrified bodies, human or otherwise, are either
based on deliberate frauds or are the result of a very erroneous
misinterpretation of facts. That the impression or cast of a body
_might_ be formed in nature, somewhat as casts have been made of those
who perished at Pompeii, is true; but, so far, no authentic case of the
kind has come to light, and the reader is quite justified in
disbelieving any report of "a petrified man."
Natural casts of such hard bodies as shells are common, formed by the
dissolving away of the original shell after it had become enclosed in
mud, or even after this had changed to stone, and the filling up of this
space by the filtering in of water charged with lime or silica, which
is there deposited, often in crystalline form. In this way, too, are
formed casts of eggs of reptiles and birds, so perfect that it is
possible to form a pretty accurate opinion as to the group to which they
belong.
[Illustration: Fig. 2.--Bryozoa from the Shore of the Devonian Sea that
Covered Eastern New York. _From a specimen in Yale University Museum,
prepared by Dr. Beecher._]
Sometimes it happens that shells or other small objects imbedded in
limestone have been dissolved and replaced by silica, and in such cases
it is possible to eat away the enveloping rock with acid and leave the
silicified casts. By this method specimens of shells, corals, and
bryozoans are obtained of almost lace-like delicacy, and as perfect as
if only yesterday gathered at the sea-shore. Casts of the interior of
shells, showing many details of structure, are common, and anyone who
has seen clams dug will understand how they are formed by the entrance
of mud into the empty shell.
Casts of the kernels of nuts are formed in much the same way, and
Professor E. H. Barbour has thus described the probable manner in which
this was done. When the nuts were dropped into the water of the ancient
lake the kernel rotted away, but the shell, being tough and hard, would
probably last for years under favorable circumstances. Throughout the
marls and clays of the Bad Lands (of South Dakota) there is a large
amount of potash. This is dissolved by water, and then acts upon quartz,
carrying it away in solution. This would find its way by infiltration
into the interior of the nut. At the same time with this process,
carrying lime carbonate in solution was going on, so that doubtless the
stone kernels, consisting of pretty nearly equal parts of lime and
silica, were deposited within the nuts. These kernels, of course, became
hard and flinty in time, and capable of resisting almost any amount of
weathering. Not so the organic shell; this eventually would decay away,
and so leave the filling or kernel of chalcedony and lime.[1]
[1] _Right here is the weak spot in Professor Barbour's explanation, and
an illustration of our lack of knowledge. For it is difficult to see why
the more enduring husk should not have become mineralized equally with
the cavity within._
"Fossil leaves" are nothing but fine casts, made in natural moulds, and
all have seen the first stages in their formation as they watched the
leaves sailing to the ground to be covered by mud or sand at the next
rain, or dropping into the water, where sooner or later they sink, as we
may see them at the bottom of any quiet woodland spring.
Impressions of leaves are among the early examples of color-printing,
for they are frequently of a darker, or even different, tint from that
of the surrounding rock, this being caused by the carbonization of
vegetable matter or to its action on iron that may have been present in
the soil or water. Besides complete mineralization, or petrifaction,
there are numerous cases of incomplete or semi-fossilization, where
modern objects, still retaining their phosphate of lime and some animal
matter even, are found buried in rock. This takes place when water
containing carbonate of lime, silica, or sometimes iron, flows over beds
of sand, cementing the grains into solid but not dense rock, and at the
same time penetrating and uniting with it such things as chance to be
buried. In this way was formed the "fossil man" of Guadeloupe, West
Indies, a skeleton of a modern Carib lying in recent concretionary
limestone, together with shells of existing species and fragments of
pottery. In a similar way, too, human remains in parts of Florida have,
through the infiltration of water charged with iron, become partially
converted into limonite iron ore; and yet we know that these bones have
been buried within quite recent times.
Sometimes we hear of springs or waters that "turn things into stone,"
but these tales are quite incorrect. Waters there are, like the
celebrated hot springs of Auvergne, France, containing so much carbonate
of lime in solution that it is readily deposited on objects placed
therein, coating them more or less thickly, according to the length of
time they are allowed to remain. This, however, is merely an
encrustation, not extending into the objects. In a similar way the
precipitation of solid material from waters of this description forms
the porous rock known as tufa, and this often encloses moss, twigs, and
other substances that are in no way to be classed with fossils.
But some streams, flowing over limestone rocks, take up considerable
carbonate of lime, and this may be deposited in water-soaked logs,
replacing more or less of the woody tissue and thus really partially
changing the wood into stone.
The very rocks themselves may consist largely of fossils; chalk, for
example, is mainly made up of the disintegrated shells of simple marine
animals called foraminifers, and the beautiful flint-like "skeletons" of
other small creatures termed radiolarians, minute as they are, have
contributed extensively to the formation of some strata.
Even after an object has become fossilized, it is far from certain that
it will remain in good condition until found, while the chance of its
being found at all is exceedingly small. When we remember that it is
only here and there that nature has made the contents of the rocks
accessible by turning the strata on edge, heaving them into cliffs or
furrowing them with valleys and canyons, we realize what a vast number
of pages of the fossil record must remain not only unread, but unseen.
The wonder is, not that we know so little of the history of the past,
but that we have learned so much, for not only is nature careless in
keeping the records--preserving them mostly in scattered fragments--but
after they have been laid away and sealed up in the rocks they are
subject to many accidents. Some specimens get badly flattened by the
weight of subsequently deposited strata, others are cracked and twisted
by the movements of the rocks during periods of upheaval or subsidence,
and when at last they are brought to the surface, the same sun and rain,
snow and frost, from which they once escaped, are ready to renew the
attack and crumble even the hard stone to fragments. Such, very briefly,
are some of the methods by which fossils may be formed, such are some of
the accidents by which they may be destroyed; but this description must
be taken as a mere outline and as applying mainly to vertebrates, or
backboned animals, since it is with them that we shall have to deal. It
may, however, show why it is that fossils are not more plentiful, why we
have mere hints of the existence of many animals, and why myriads of
creatures may have flourished and passed away without so much as leaving
a trace of their presence behind.
_REFERENCES_
_A very valuable and interesting article by Dr. Charles A. White,
entitled "The Relation of Biology to Geological Investigation," will be
found in the Report of the United States National Museum for 1892. This
comprises a series of essays on the nature and scientific uses of fossil
remains, their origin, relative chronological value and other questions
pertaining to them. The United States National Museum has published a
pamphlet, part K, Bulletin 39, containing directions for collecting and
preparing fossils, by Charles Schuchert; and another, part B, Bulletin
39, collecting recent and fossil plants, by F. H. Knowlton._
[Illustration: Fig. 3.--Skeleton of a Radiolarian Very Greatly
Enlarged.]
II
THE EARLIEST KNOWN VERTEBRATES
"_We are the ancients of the earth
And in the morning of the times._"
There is a universal, and perfectly natural, desire for information,
which in ourselves we term thirst for knowledge and in others call
curiosity, that makes mankind desire to know how everything began and
causes much speculation as to how it all will end. This may take the
form of a wish to know how a millionaire made his first ten cents, or it
may lead to the questions--What is the oldest animal? or, What is the
first known member of the great group of backboned animals at whose head
man has placed himself? and, What did this, our primeval and
many-times-removed ancestor, look like? The question is one that has
ever been full of interest for naturalists, and Nature has been
interrogated in various ways in the hope that she might be persuaded to
yield a satisfactory answer. The most direct way has been that of
tracing back the history of animal life by means of fossil remains, but
beyond a certain point this method cannot go, since, for reasons stated
in various places in these pages, the soft bodies of primitive animals
are not preserved. To supplement this work, the embryologist has studied
the early stages of animals, as their development throws a side-light on
their past history. And, finally, there is the study of the varied forms
of invertebrates, some of which have proved to be like vertebrates in
part of their structure, while others have been revealed as vertebrates
in disguise. So far these various methods have yielded various answers,
or the replies, like those of the Delphic Oracle, have been variously
interpreted so that vertebrates are considered by some to have descended
from the worms, while others have found their beginnings in some animal
allied to the King Crab.
Every student of genealogy knows only too well how difficult a matter it
is to trace a family pedigree back a few centuries, how soon the family
names become changed, the line of descent obscure, and how soon gaps
appear whose filling in requires much patient research. How much more
difficult must it be, then, to trace the pedigree of a race that
extends, not over centuries, but thousands of centuries; how wide must
be some of the gaps, how very different may the founders of the family
be from their descendants! The words old and ancient that we use so
often in speaking of fossils appeal to us somewhat vaguely, for we speak
of the ancient civilizations of Greece and Rome, and call a family old
that can show a pedigree running back four or five hundred years, when
such as these are but affairs of yesterday compared with even recent
fossils.
Perhaps we may better appreciate the meaning of these words by recalling
that, since the dawn of vertebrate life, sufficient of the earth's
surface has been worn away and washed into the sea to form, were the
strata piled directly one upon the other, fifteen or twenty miles of
rock. This, of course, is the sum total of sedimentary rocks, for such a
thickness as this is not to be found at any one locality; because,
during the various ups and downs that this world of ours has met with,
those portions that chanced to be out of water would receive no deposit
of mud or sand, and hence bear no corresponding stratum of rock. The
reader may think that there is a great deal of difference between
fifteen and twenty miles, but this liberal margin is due to the
difficulty of measuring the thickness of the rocks, and in Europe the
sum of the measurable strata is much greater than in North America.
The earliest traces of animal life are found deeper still, beneath
something like eighteen to twenty-five miles of rock, while below this
level are the strata in which dwelt the earliest living things,
organisms so small and simple that no trace of their existence has been
left, and we infer that they were there because any given group starts
in a modest way with small and simple individuals.
At the bottom, then, of twenty miles of rocks the seeker for the
progenitor of the great family of backboned animals finds the scant
remains of fish-like animals that the cautious naturalist, who is much
given to "hedging," terms, not vertebrates, but prevertebrates or the
forerunners of backboned animals. The earliest of these consist of small
bony plates, and traces of a cartilaginous backbone from the Lower
Silurian of Colorado, believed to represent relatives of Chimæra and
species related to those better-known forms Holoptychius and Osteolepis,
which occur in higher strata. There are certainly indications of
vertebrate life, but the remains are so imperfect that little more can
be said regarding them, and this is also true of the small conical teeth
which occur in the Lower Silurian of St. Petersburg, and are thought to
be the teeth of some animal like the lamprey.
A little higher up in the rocks, though not in the scale of life, in the
Lower Old Red Sandstone of England, are found more numerous and better
preserved specimens of another little fish-like creature, rarely if ever
exceeding two inches in length, and also related (probably) to the
hag-fishes and lampreys that live to-day.
These early vertebrates are not only small, but they were cartilaginous,
so that it was essential for their preservation that they should be
buried in soft mud as soon as possible after death. Even if this took
place they were later on submitted to the pressure of some miles of
overlying rock until, in some cases, their remains have been pressed out
thinner than a sheet of paper, and so thoroughly incorporated into the
surrounding stone that it is no easy matter to trace their shadowy
outlines. With such drawbacks as these to contend with, it can scarcely
be wondered at that, while some naturalists believe these little
creatures to be related to the lamprey, others consider that they belong
to a perfectly distinct group of animals, and others still think it
possible that they may be the larval or early stages of larger and
better-developed forms.
Still higher up we come upon the abundant remains of numerous small
fish-like animals, more or less completely clad in bony armor,
indicating that they lived in troublous times when there was literally a
fight for existence and only such as were well armed or well protected
could hope to survive. A parallel case exists to-day in some of the
rivers of South America, where the little cat-fishes would possibly be
eaten out of existence but for the fact that they are covered--some of
them very completely--with plate-armor that enables them to defy their
enemies, or renders them such poor eating as not to be worth the taking.
The arrangement of the plates or scales in the living Loricaria is very
suggestive of the series of bony rings covering the body of the ancient
Cephalaspis, only the latter, so far as we know, had no side-fins; but
the creatures are in no wise related, and the similarity is in
appearance only.
[Illustration: Fig. 4.--Cephalaspis and Loricaria, an Ancient and a
Modern Armored Fish.]
Pterichthys, the wing fish, was another small, quaint, armor-clad
creature, whose fossilized remains were taken for those of a crab, and
once described as belonging to a beetle. Certainly the buckler of this
fish, which is the part most often preserved, with its jointed, bony
arms, looks to the untrained eye far more like some strange crustacean
than a fish, and even naturalists have pictured the animal as crawling
over the bare sands by means of those same arms. These fishes and their
allies were once the dominant type of life, and must have abounded in
favored localities, for in places are great deposits of their protective
shields jumbled together in a confused mass, and, save that they have
hardened into stone, lying just as they were washed up on the ancient
beach ages ago. How abundant they were may be gathered from the fact
that it is believed their bodies helped consolidate portions of the
strata of the English Old Red Sandstone. Says Mr. Hutchinson, speaking
of the Caithness Flagstones, "They owe their peculiar tenacity and
durability to the dead fishes that rotted in their midst while yet they
were only soft mud. For just as a plaster cast boiled in oil becomes
thereby denser and more durable, so the oily and other matter coming
from decomposing fish operated on the surrounding sand or mud so as to
make it more compact."
It may not be easy to explain how it came to pass that fishes dwelling
in salt water, as these undoubtedly did, were thus deposited in great
numbers, but we may now and then see how deposits of fresh-water fishes
may have been formed. When rivers flowing through a stretch of level
country are swollen during the spring floods, they overflow their banks,
often carrying along large numbers of fishes. As the water subsides
these may be caught in shallow pools that soon dry up, leaving the
fishes to perish, and every year the Illinois game association rescues
from the "back waters" quantities of bass that would otherwise be lost.
Mr. F. S. Webster has recorded an instance that came under his
observation in Texas, where thousands of gar pikes, trapped in a lake
formed by an overflow of the Rio Grande, had been, by the drying up of
this lake, penned into a pool about seventy-five feet long by
twenty-five feet wide. The fish were literally packed together like
sardines, layer upon layer, and a shot fired into the pool would set the
entire mass in motion, the larger gars as they dashed about casting the
smaller fry into the air, a score at a time. Mr. Webster estimates that
there must have been not less than 700 or 800 fish in the pool, from a
foot and a half up to seven feet in length, every one of which perished
a little later. In addition to the fish in the pond, hundreds of those
that had died previously lay about in every direction, and one can
readily imagine what a fish-bed this would have made had the occurrence
taken place in the past.
From the better-preserved specimens that do now and then turn up, we are
able to obtain a very exact idea of the construction of the bony cuirass
by which Pterichthys and its American cousin were protected, and to make
a pretty accurate reconstruction of the entire animal. These primitive
fishes had mouths, for eating is a necessity; but these mouths were not
associated with true jaws, for the two do not, as might be supposed,
necessarily go together. Neither did these animals possess hard
backbones, and, while Pterichthys and its relatives had arms or fins,
the hard parts of these were not on the inside but on the outside, so
that the limb was more like the leg of a crab than the fin of a fish;
and this is among the reasons why some naturalists have been led to
conclude that vertebrates may have developed from crustaceans.
Pteraspis, another of these little armored prevertebrates, had a less
complicated covering, and looked very much like a small fish with its
fore parts caught in an elongate clam-shell.
The fishes that we have so far been considering--orphans of the past
they might be termed, as they have no living relatives--were little
fellows; but their immediate successors, preserved in the Devonian
strata, particularly of North America, were the giants of those days,
termed, from their size and presumably fierce appearance, Titantichthys
and Dinichthys, and are related to a fish, _Ceratodus_, still living in
Australia.
We know practically nothing of the external appearance of these fishes,
great and fierce though they may have been, with powerful jaws and
armored heads, for they had no bony skeleton--as if they devoted their
energies to preying upon their neighbors rather than to internal
improvements. They attained a length of ten to eighteen feet, with a
gape, in the large species called Titanichthys, of four feet, and such a
fish might well be capable of devouring anything known to have lived at
that early date.
Succeeding these, in Carboniferous times, came a host of shark-like
creatures known mainly from their teeth and spines, for their skeletons
were of cartilage, and belonging to types that have mostly perished,
giving place to others better adapted to the changed conditions wrought
by time. Almost the only living relative of these early fishes is a
little shark, known as the Port Jackson Shark, living in Australian
waters. Like the old sharks, this one has a spine in front of his back
fins, and, like them, he fortunately has a mouthful of diversely shaped
teeth; fortunately, because through their aid we are enabled to form
some idea of the manner in which some of the teeth found scattered
through the rocks were arranged. For the teeth were not planted in
sockets, as they are in higher animals, but simply rested on the jaws,
from which they readily became detached when decomposition set in after
death. To complicate matters, the teeth in different parts of the jaws
were often so unlike one another that when found separately they would
hardly be suspected of having belonged to the same animal. Besides teeth
these fishes, for purposes of offence and defence, were usually armed
with spines, sometimes of considerable size and strength, and often
elaborately grooved and sculptured. As the soft parts perished the teeth
and spines were left to be scattered by waves and currents, a tooth
here, another there, and a spine somewhere else; so it has often
happened that, being found separately, two or three quite different
names have been given to one and the same animal. Now and then some
specimen comes to light that escaped the thousand and one accidents to
which such things were exposed, and that not only shows the teeth and
spines but the faint imprint of the body and fins as well. And from such
rare examples we learn just what teeth and spines go with one another,
and sometimes find that one fish has received names enough for an entire
school.
These ancient sharks were not the large and powerful fishes that we have
to-day--these came upon the scene later--but mostly fishes of small
size, and, as indicated by their spines, fitted quite as much for
defence as offence. Their rise was rapid, and in their turn they became
the masters of the world, spreading in great numbers through the waters
that covered the face of the earth; but their supremacy was of short
duration, for they declined in numbers even during the Carboniferous
Period, and later dwindled almost to extinction. And while sharks again
increased, they never reached their former abundance, and the species
that arose were swift, predatory forms, better fitted for the struggle
for existence.
_REFERENCES_
_The early fishes make but little show in a museum, both on account of
their small size and the conditions under which they have been
preserved. The Museum of Comparative Zoölogy has a large collection of
these ancient vertebrates, and there is a considerable number of fine
teeth and spines of Carboniferous sharks in the United States National
Museum._
_Hugh Miller's "The Old Red Sandstone" contains some charming
descriptions of his discoveries of Pterichthys and related forms, and
this book will ever remain a classic._
[Illustration: Fig. 5.--Pterichthys, the Wing Fish.]
III
IMPRESSIONS OF THE PAST
"_The weird palimpsest, old and vast,
Wherein thou hid'st the spectral past._"
The Rev. H. N. Hutchinson commences one of his interesting books with
Emerson's saying, "that Everything in nature is engaged in writing its
own history;" and, as this remark cannot be improved on, it may well
stand at the head of a chapter dealing with the footprints that the
creatures of yore left on the sands of the sea-shore, the mud of a
long-vanished lake bottom, or the shrunken bed of some water-course. Not
only have creatures that walked left a record of their progress, but the
worms that burrowed in the sand, the shell-fish that trailed over the
mud when the tide was low, the stranded crab as he scuttled back to the
sea--each and all left some mark to tell of their former presence. Even
the rain that fell and the very wind that blew sometimes recorded the
direction whence they came, and we may read in the rocks, also, accounts
of freshets sweeping down with turbid waters, and of long periods of
drouth, when the land was parched and lakes and rivers shrank beneath
the burning sun.
All these things have been told and retold; but, as there are many who
have not read Mr. Hutchinson's books and to whom Buckland is quite
unknown, it may be excusable to add something to what has already been
said in the first chapter of these impressions of the past.
The very earliest suggestion we have of the presence of animal life upon
this globe is in the form of certain long dark streaks below the
Cambrian of England, considered to be traces of the burrows of worms
that were filled with fine mud, and while this interpretation may be
wrong there is, on the other hand, no reason why it may not be correct.
Plant and animal life must have had very lowly beginnings, and it is not
at all probable that we shall find any trace of the simple and minute
forms with which they started,[2] though we should not be surprised at
finding hints of the presence of living creatures below the strata in
which their remains are actually known to occur.
[2] _Within the last few years what are believed to be indications of
bacteria have been described from carboniferous rocks. Naturally such
announcements must be accepted with great caution, for while there is no
reason why this may not be true, it is much more probable that definite
evidence of the effects of bacteria on plants should be found than that
these simple, single-celled organisms should themselves have been
detected._
Worm burrows, to be sure, are hardly footprints, but tracks are found in
Cambrian rocks just above the strata in which the supposed burrows
occur, and from that time onward there are tracks a-plenty, for they
have been made, wherever the conditions were favorable, ever since
animals began to walk. All that was needed was a medium in which
impressions could be made and so filled that there was imperfect
adhesion between mould and matrix. Thus we find them formed not only by
the sea-shore, in sands alternately dry and covered, but by the
river-side, in shallow water, or even on land where tracks might be left
in soft or moist earth into which wind-driven dust or sand might lodge,
or sand or mud be swept by the mimic flood caused by a thunder shower.
So there are tracks in strata of every age; at first those of
invertebrates: after the worm burrows the curious complicated trails of
animals believed to be akin to the king crab; broad, ribbed, ribbon-like
paths ascribed to trilobites; then faint scratches of insects, and the
shallow, palmed prints of salamanders, and the occasional slender sprawl
of a lizard; then footprints, big and little, of the horde of Dinosaurs
and, finally, miles above the Cambrian, marks of mammals. Sometimes,
like the tracks of salamanders and reptiles in the carboniferous rocks
of Pennsylvania and Kansas, these are all we have to tell of the
existence of air-breathing animals. Again, as with the iguanodon, the
foot to fit the track may be found in the same layer of rock, but this
is not often the case.
Although footprints in the rocks must often have been seen, they seem to
have attracted little or no notice from scientific men until about 1830
to 1835, when they were almost simultaneously described both in Europe
and America; even then, it was some time before they were generally
conceded to be actually the tracks of animals, but, like worm burrows
and trails, were looked upon as the impressions of sea-weeds.
The now famous tracks in the "brown stone" of the Connecticut Valley
seem to have first been seen by Pliny Moody in 1802, when he ploughed up
a specimen on his farm, showing small imprints, which later on were
popularly called the tracks of Noah's raven. The discovery passed
without remark until in 1835 the footprints came under the observation
of Dr. James Deane, who, in turn, called Professor Hitchcock's attention
to them. The latter at once began a systematic study of these
impressions, publishing his first account in 1836 and continuing his
researches for many years, in the course of which he brought together
the fine collection in Amherst College. At that time Dinosaurs were
practically unknown, and it is not to be wondered at that these
three-toed tracks, great and small, were almost universally believed to
be those of birds. So it is greatly to the credit of Dr. Deane, who also
studied these footprints, that he was led to suspect that they might
have been made by other animals. This suspicion was partly caused by the
occasional association of four and five-toed prints with the three-toed
impressions, and partly by the rare occurrence of imprints showing the
texture of the sole of the foot, which was quite different from that of
any known bird.
[Illustration: Fig. 6.--Where a Dinosaur Sat Down.]
In the light of our present knowledge we are able to read many things in
these tracks that were formerly more or less obscure, and to see in them
a complete verification of Dr. Deane's suspicion that they were not made
by birds. We see clearly that the long tracks called _Anomoepus_,
with their accompanying short fore feet, mark where some Dinosaur
squatted down to rest or progressed slowly on all-fours, as does the
kangaroo when feeding quietly;[3] and we interpret the curious
heart-shaped depression sometimes seen back of the feet, not as the mark
of a stubby tail, but as made by the ends of the slender pubes, bones
that help form the hip-joints. Then, too, the mark of the inner, or
short first, toe, is often very evident, although it was a long time
before the bones of this toe were actually found, and many of the
Dinosaurs now known to have four toes were supposed to have but three.
[3] _It is to be noted that a leaping kangaroo touches the ground
neither with his heel nor his tail, but that between jumps he rests
momentarily on his toes only; hence impressions made by any creature
that jumped like a kangaroo would be very short._
It seems strange, and it is strange, that while so many hundreds of
tracks should have been found in the limited area exposed to view, so
few bones have been found--our knowledge of the veritable animals that
made the tracks being a blank. A few examples have, it is true, been
found, but these are only a tithe of those known to have existed; while
of the great animals that strode along the shore, leaving tracks fifteen
inches long and a yard apart pressed deeply into the hard sand, not a
bone remains. The probability is that the strata containing their bones
lie out to sea, whither their bodies were carried by tides and currents,
and that we may never see more than the few fragments that were
scattered along the seaside.
That part of the Valley of the Connecticut wherein the footprints are
found seems to have been a long, narrow estuary running southward from
Turner's Falls, Mass., where the tracks are most abundant and most
clear. The topography was such that this estuary was subject to sudden
and great fluctuations of the water-level, large tracts of shore being
now left dry to bake in the sun, and again covered by turbid water which
deposited on the bottom a layer of mud. Over and over again this
happened, forming layer upon layer of what is now stone, sometimes the
lapse of time between the deposits being so short that the tracks of
the big Dinosaurs extend through several sheets of stone; while again
there was a period of drouth when the shore became so dry and firm as to
retain but a single shallow impression.
[Illustration: Fig. 7.--Footprints of Dinosaurs on the Brownstone of the
Connecticut Valley. _From a slab in the museum of Amherst College._]
Something of the wealth of animal life that roamed about this estuary
may be gathered from the number of different footprints recorded on the
sands, and these are so many and so varied that Professor Hitchcock in
two extensive reports enumerated over 150 species, representing various
groups of animals. One little point must, however, be borne in mind,
that mere size is no sure indication of differences in dealing with
reptiles, for these long-lived creatures grow almost continuously
throughout life, so that one animal even may have left his footprints
over and over in assorted sizes from one end of the valley to the other.
The slab shown in Fig. 7 is a remarkably fine example of these
Connecticut River footprints; it shows in relief forty-eight tracks of
the animal called Brontozoum sillimanium and six of a lesser species.
It was quarried near Middletown, in 1778, and for sixty years did duty
as a flagstone, fortunately with the face downwards. When taken up for
repairs the tracks were discovered, and later on the slab, which
measures three by five feet, was transferred to the museum of Amherst
College.
There is an interesting parallel between the history of footprints in
England and America, for they were noticed at about the same time, 1830,
in both countries; in each case the tracks were in rocks of Triassic
age, and, in both instances, the animals that made them have never been
found. In England, however, the tracks first found were those ascribed
to tortoises, though a little later Dinosaur footprints were discovered
in the same locality. Oddly enough these numerous tracks all run one
way, from west to east, as if the animals were migrating, or were
pursuing some well-known and customary route to their feeding grounds.
For some reason Triassic rocks are particularly rich in footprints; for
from strata of this same age in the Rhine Valley come those curious
examples so like the mark of a stubby hand that Dr. Kaup christened the
beast supposed to have made them _Cheirotherium_, beast with a hand,
suggesting that they had been made by some gigantic opossum. As the
tracks measure five by eight inches, it would have been rather a large
specimen, but the mammals had not then arisen, and it is generally
believed that the impressions were made by huge (for their kind)
salamander-like creatures, known as labyrinthodonts, whose remains are
found in the same strata.
Footprints may aid greatly in determining the attitude assumed by
extinct animals, and in this way they have been of great service in
furnishing proof that many of the Dinosaurs walked erect. The
impressions on the sands of the old Connecticut estuary may be said to
show this very plainly, but in England and Belgium is evidence still
more conclusive, in the shape of tracks ascribed to the Iguanodon. These
were made on soft soil into which the feet sank much more deeply than in
the Connecticut sands, and the casts made in the natural moulds show the
impression of toes very clearly. If the animals had walked flat-footed,
as we do, the prints of the toes would have been followed by a long heel
mark, but such is not the case; there are the sharply defined marks of
the toes and nothing more, showing plainly that the Iguanodons walked,
like birds, on the toes alone. More than this, had these Dinosaurs
dragged their tails there would have been a continuous furrow between
the footprints; but nothing of this sort is to be found; on the
contrary, a fine series of tracks, uncovered at Hastings, England, made
by several individuals and running for seventy-five feet, shows
footprints only. Hence it may be fairly concluded that these great
creatures carried their tails clear of the ground, as shown in the
picture of _Thespesius_, the weight of the tail counterbalancing that of
the body. Where crocodilians or some of the short-limbed Dinosaurs have
crept along there is, as we should expect, a continuous furrow between
the imprints of the feet. This is what footprints tell us when their
message is read aright; when improperly translated they only add to the
enormous bulk of our ignorance.
Some years ago we were treated to accounts of wonderful footprints in
the rock of the prison-yard at Carson City, Nev., which, according to
the papers, not only showed that men existed at a much earlier period
than the scientific supposed, but that they were men of giant stature.
This was clearly demonstrated by the footprints, for they were such as
_might_ have been made by huge moccasined feet, and this was all that
was necessary for the conclusion that they _were_ made by just such
feet. For it is a curious fact that the majority of mankind seem to
prefer any explanation other than the most simple and natural,
particularly in the case of fossils, and are always looking for a
primitive race of gigantic men.
Bones of the Mastodon and Mammoth have again and again been eagerly
accepted as those of giants; a salamander was brought forward as
evidence of the deluge (_homo diluvii testis_); ammonites and their
allies pose as fossil snakes, and the "petrified man" flourishes
perennially. However, in this case the prints were recognized by
naturalists as having most probably been made by some great ground
sloth, such as the Mylodon or Morotherium, these animals, though
belonging to a group whose headquarters were in Patagonia, having
extended their range as far north as Oregon. That the tracks seemed to
have been made by a biped, rather than a quadruped, was due to the fact
that the prints of the hind feet fell upon and obliterated the marks of
the fore. Still, a little observation showed that here and there prints
of the fore feet were to be seen, and on one spot were indications of a
struggle between two of the big beasts. The mud, or rather the stone
that had been mud, bears the imprints of opposing feet, one set deeper
at the toes, the other at the heels, as if one animal had pushed and the
other resisted. In the rock, too, are broad depressions bearing the
marks of coarse hair, where one creature had apparently sat on its
haunches in order to use its fore limbs to the best advantage. Other
footprints there are in this prison-yard; the great round "spoor" of the
mammoth, the hoofs of a deer, and the paws of a wolf(?), indicating that
hereabout was some pool where all these creatures came to drink. More
than this, we learn that when these prints were made, or shortly after,
a strong wind blew from the southeast, for on that face of the ridges
bounding the margin of each big footprint, we find sand that lodged
against the squeezed-up mud and stuck there to serve as a perpetual
record of the direction of the wind.
_REFERENCES_
_Almost every museum has some specimen of the Connecticut Valley
footprints, but the largest and finest collections are in the museums of
Amherst College, Mass., and Yale University, although, owing to lack of
room, only a few of the Yale specimens are on exhibition. The collection
at Amherst comprises most of the types described by Professor E.
Hitchcock in his "Ichnology of New England," a work in two fully
illustrated quarto volumes. Other footprints are described and figured
by Dr. J. Deane in "Ichnographs from the Sandstone of the Connecticut
River."_
[Illustration: Fig. 8.--The Track of a Three-toed Dinosaur.]
IV
RULERS OF THE ANCIENT SEAS
"_A time there was when the universe was darkness and water,
wherein certain animals of frightful and compound mien were
generated. There were serpents, and other creatures with the
mixed shapes of one another...._"--_The Archaic Genesis._
History shows us how in the past nation after nation has arisen,
increased in size and strength, extended its bounds and dominion until
it became the ruling power of the world, and then passed out of
existence, often so completely that nothing has remained save a few
mounds of dirt marking the graves of former cities. And so has it been
with the kingdoms of nature. Just as Greece, Carthage, and Rome were
successively the rulers of the sea in the days that we call old, so,
long before the advent of man, the seas were ruled by successive races
of creatures whose bones now lie scattered over the beds of the ancient
seas, even as the wrecks of galleys lie strewn over the bed of the
Mediterranean. For a time the armor-clad fishes held undisputed sway;
then their reign was ended by the coming of the sharks, who in their
turn gave way to the fish-lizards, the Ichthyosaurs and Plesiosaurs.
These, however, were rather local in their rule; but the next group of
reptiles to appear on the scene, the great marine reptiles called
Mosasaurs, practically extended their empire around the world, from New
Zealand to North America.
We properly call these reptiles great, for so they were; but there are
degrees of greatness, and there is a universal tendency to think of the
animals that have become extinct as much greater than those of the
present day, to magnify the reptile that we never saw as well as the
fish that "got away," and it may be safely said that the greatest of
animals will shrink before a two-foot rule. As a matter of fact, no
animals are known to have existed that were larger than the whales; and,
while there are now no reptiles that can compare in bulk with the
Dinosaurs, there were few Mosasaurs that exceeded in size a first-class
Crocodile. An occasional Mosasaur reaches a length of forty feet, but
such are rare indeed, and one even twenty-five feet long is a large
specimen,[4] while the great Mugger, or Man-eating Crocodile, grows, if
permitted, to a length of twenty-five or even thirty feet, and need not
be ashamed to match his bulk and jaws against those of most Mosasaurs.
[4] _It is surprising to find Professor Cope placing the length of the
Mosasaurs at 70, 80, or 100 feet, as there is not the slightest basis
for even the lowest of these figures. Professor Williston, the best
authority on the subject, states, in his volume on the "Cretaceous
Reptiles of Kansas," that there is not in existence any specimen of a
Mosasaur indicating a greater length than 45 feet._
The first of these sea-reptiles to be discovered has passed into
history, and now reposes in the Jardin des Plantes, Paris, after
changing hands two or three times, the original owner being dispossessed
of his treasure by the subtleties of law, while the next holder was
deprived of the specimen by main force. Thus the story is told by M.
Faujas St. Fond, as rendered into English, in Mantell's "Petrifactions
and their Teachings": "Some workmen, in blasting the rock in one of the
caverns of the interior of the mountain, perceived, to their
astonishment, the jaws of a large animal attached to the roof of the
chasm. The discovery was immediately made known to M. Hoffman, who
repaired to the spot, and for weeks presided over the arduous task of
separating the mass of stone containing these remains from the
surrounding rock. His labors were rewarded by the successful extrication
of the specimen, which he conveyed in triumph to his house. This
extraordinary discovery, however, soon became the subject of general
conversation, and excited so much interest that the canon of the
cathedral which stands on the mountain resolved to claim the fossil, in
right of being lord of the manor, and succeeded, after a long and
harassing lawsuit, in obtaining the precious relic. It remained for
years in his possession, and Hoffman died without regaining his
treasure. At length the French Revolution broke out, and the armies of
the Republic advanced to the gates of Maestricht. The town was
bombarded; but, at the suggestion of the committee of savans who
accompanied the French troops to select their share of the plunder, the
artillery was not suffered to play on that part of the city in which the
celebrated fossil was known to be preserved. In the meantime, the canon
of St. Peter's, shrewdly suspecting the reason why such peculiar favor
was shown to his residence, removed the specimen and concealed it in a
vault; but, when the city was taken, the French authorities compelled
him to give up his ill-gotten prize, which was immediately transmitted
to the Jardin des Plantes, at Paris, where it still forms one of the
most interesting objects in that magnificent collection." And there it
remains to this day.
[Illustration: Fig. 9.--A Great Sea Lizard, _Tylosaurus Dyspelor_. _From
a drawing by J. M. Gleeson._]
The seas that rolled over western Kansas were the headquarters of the
Mosasaurs, and hundreds--aye, thousands--of specimens have been taken
from the chalk bluffs of that region, some of them in such a fine state
of preservation that we are not only well acquainted with their internal
structure, but with their outward appearance as well. They were
essentially swimming lizards--great, overgrown, and distant relatives of
the Monitors of Africa and Asia, especially adapted to a roving,
predatory life by their powerful tails and paddle-shaped feet. Their
cup-and-ball vertebræ indicate great flexibility of the body, their
sharp teeth denote ability to capture slippery prey, and the structure
of the lower jaw shows that they probably ate in a hurry and swallowed
their food entire, or bolted it in great chunks. The jaws of all
reptiles are made up of a number of pieces, but these are usually so
spliced together that each half of the jaw is one inflexible, or nearly
inflexible, mass of bone. In snakes, which swallow their prey entire,
the difficulty of swallowing animals greater in diameter than themselves
is surmounted by having the two halves of the lower jaw loosely joined
at the free ends, so that these may spread wide apart and thus increase
the gape of the mouth. This is also helped by the manner in which the
jaw is joined to the head. The pelican solves the problem by the length
of his mandibles, this allowing so much spring that when open they bow
apart to form a nice little landing net. In the Mosasaurs, as in the
cormorants, among birds, there is a sort of joint in each half of the
lower jaw which permits it to bow outward when opened, and this, aided
by the articulation of the jaw with the cranium, adds greatly to the
swallowing capacity. Thus in nature the same end is attained by very
different methods. To borrow a suggestion from Professor Cope, if the
reader will extend his arms at full length, the palms touching, and then
bend his elbows outward he will get a very good idea of the action of a
Mosasaur's jaw. The western sea was a lively place in the day of the
great Mosasaurs, for with them swam the king of turtles, Archelon, as
Mr. Wieland has fitly named him, a creature a dozen feet or more in
length, with a head a full yard long, while in the shallows prowled
great fishes with massive jaws and teeth like spikes.
[Illustration: Fig. 10.--Jaw of a Mosasaur, Showing the Joint that
Increased the Swallowing Capacity of that Reptile.]
There, too, was the great, toothed diver, Hesperornis (see page 83),
while over the waters flew pterodactyls, with a spread of wing of twenty
feet, largest of all flying creatures; and, not improbably--nay, very
probably--fish-eaters, too; and when each and all of these were seeking
their dinners, there were troublous times for the small fry in that old
Kansan sea.
And then there came a change; to the south, to the west, to the north,
the land was imperceptibly but surely rising, perhaps only an inch or
two in a century, but still rising, until "The Ocean in which flourished
this abundant and vigorous life was at last completely inclosed on the
west by elevations of sea-bottom, so that it only communicated with the
Atlantic and Pacific at the Gulf of Mexico and the Arctic Sea."
The continued elevation of both eastern and western shores contracted
its area, and when ridges of the sea-bottom reached the surface, forming
long, low bars, parts of the water-area were included, and connection
with salt-water prevented. Thus were the living beings imprisoned and
subjected to many new risks to life. The stronger could more readily
capture the weaker, while the fishes would gradually perish through the
constant freshening of the water. With the death of any considerable
class, the balance of food-supply would be lost, and many large species
would disappear from the scene. The most omnivorous and enduring would
longest resist the approach of starvation, but would finally yield to
inexorable fate--the last one caught by the shifting bottom among
shallow pools, from which his exhausted energies could not extricate
him.[5]
[5] _Cope: "The Vertebrata of the Cretaceous Formations of the West," p.
50, being the "Report of the United States Geological Survey of the
Territories," Vol. II._
Like the "Fossil man" the sea-serpent flourishes perennially in the
newspapers and, despite the fact that he is now mainly regarded as a
joke, there have been many attempts to habilitate this mythical monster
and place him on a foundation of firm fact. The most earnest of these
was that of M. Oudemans, who expressed his belief in the existence of
some rare and huge seal-like creature whose occasional appearance in
southern waters gave rise to the best authenticated reports of the
sea-serpent. Among other possibilities it has been suggested that some
animal believed to be extinct had really lived over to the present day.
Now there are a few waifs, spared from the wrecks of ancient faunas,
stranded on the shores of the present, such as the Australian Ceratodus
and the Gar Pikes of North America, and these and all other creatures
that could be mustered in were used as proofs to sustain this theory.
If, it was said, these animals have been spared, why not others? If a
fish of such ancient lineage as the Gar Pike is so common as to be a
nuisance, why may there not be a few Plesiosaurs or a Mosasaur somewhere
in the depths of the ocean? The argument was a good one, the more that
we may "suppose" almost anything, but it must be said that no trace of
any of these creatures has so far been found outside of the strata in
which they have long been known to occur, and all the probabilities are
opposed to this theory. Still, if some of these creatures _had_ been
spared, they might well have passed for sea-serpents, even though
Zeuglodon, the one most like a serpent in form, was the one most
remotely related to snakes.
Zeuglodon, the yoke-tooth, so named from the shape of its great cutting
teeth, was indeed a strange animal, and if we wonder at the Greenland
Whale, whose head is one-third its total length, we may equally wonder
at Zeuglodon, with four feet of head, ten feet of body, and forty feet
of tail. No one, seeing the bones of the trunk and tail for the first
time, would suspect that they belonged to the same animal, for while the
vertebræ of the body are of moderate size, those of the tail are, for
the bulk of creature, the longest known, measuring from fifteen to
eighteen inches in length, and weighing in a fossil condition fifty to
sixty pounds. In life, the animal was from fifty to seventy feet in
length, and not more than six or eight feet through the deepest part of
the body, while the tail was much less; the head was small and pointed,
the jaws well armed with grasping and cutting teeth, and just back of
the head was a pair of short paddles, not unlike those of a fur seal. It
is curious to speculate on the habits of a creature in which the tail
so obviously wagged the dog and whose articulations all point to great
freedom of movement up and down. This may mean that it was an active
diver, descending to great depths to prey upon squid, as the Sperm-Whale
does to-day, while it seems quite certain that it must have reared at
least a third of its great length out of water to take a comprehensive
view of its surroundings. And if size is any indication of power, the
great tail, which obviously ended in flukes like those of a whale, must
have been capable of propelling the beast at a speed of twenty or thirty
miles an hour. Something of the kind must have been needed in order that
the small head might provide food enough for the great tail, and it has
been suggested that inability to do this was the reason why Zeuglodon
became extinct. On the other hand, it has been ingeniously argued that
the huge tail served to store up fat when food was plenty, which was
drawn upon when food became scarce. The fur seals do something similar
to this, for the males come on shore in May rolling in blubber, and
depart in September lean and hungry after a three months' fast.
Zeuglodons must have been very numerous in the old Gulf of Mexico, for
bones are found abundantly through portions of our Southern States; it
was also an inhabitant of the old seas of southern Europe, but, as we
shall see, it gave place to the great fossil shark, and this in turn
passed out of existence. Still, common though its bones may be, stories
of their use for making stone walls--and these stories are still in
circulation--resolve themselves on close scrutiny into the occasional
use of a big vertebra to support the corner of a corn-crib.
The scientific name of Zeuglodon is _Basilosaurus cetoides_, the
whale-like king lizard--the first of these names, _Basilosaurus_, having
been given to it by the original describer, Dr. Harlan, who supposed the
animal to have been a reptile. Now it is a primary rule of nomenclature
that the first name given to an animal must stick and may not be
changed, even by the act of a zoölogical congress, so Zeuglodon must, so
far as its name is concerned, masquerade as a reptile for the rest of
its paleontological life. This, however, really matters very little,
because scientific names are simply verbal handles by which we may grasp
animals to describe them, and Dr. Le Conte, to show how little there may
be in a name, called a beetle Gyascutus. Owen's name of Zeuglodon,
although not tenable as a scientific name, is too good to be wasted, and
being readily remembered and easily pronounced may be used as a popular
name.
[Illustration: Fig. 11.--Koch's Hydrarchus, Composed of Portions of the
Skeleton of Several Zeuglodons.]
One might think that a creature sixty or seventy feet long was amply
long enough, but Dr. Albert Koch thought otherwise, and did with
Zeuglodon as, later on, he did with the Mastodon, combining the vertebræ
of several individuals until he had a monster 114 feet long! This he
exhibited in Europe under the name of Hydrarchus, or water king, finally
disposing of the composite creature to the Museum of Dresden, where it
was promptly reduced to its proper dimensions. The natural make-up of
Zeuglodon is sufficiently composite without any aid from man, for the
head and paddles are not unlike those of a seal, the ribs are like those
of a manatee, and the shoulder blades are precisely like those of a
whale, while the vertebræ are different from those of any other animal,
even its own cousin and lesser contemporary Dorudon. There were also
tiny hind legs tucked away beneath skin, but these, as well as many
other parts of the animal's structure were unknown, until Mr. Charles
Schuchert collected a series of specimens for the National Museum, from
which it was possible to restore the entire skeleton. Owing to a rather
curious circumstance the first attempt at a restoration was at fault;
among the bones originally obtained by Mr. Schuchert there were none
from the last half of the tail, an old gully having cut off the hinder
portion of the backbone and destroyed the vertebræ. Not far away,
however, was a big lump of stone containing several vertebræ of just the
right size, and these were used as models to complete the papier-maché
skeleton shown at Atlanta, in 1894. But a year after Mr. Schuchert
collected a series of vertebræ, beginning with the tip of the tail, and
these showed conclusively that the first lot of tail vertebræ belonged
to a creature still undescribed and one probably more like a whale than
Zeuglodon himself, whose exact relationships are a little uncertain, as
may be imagined from what was said of its structure. Mixed with the
bones of Zeuglodon was the shell of a turtle, nearly three feet long,
and part of the backbone of a great water-snake that must have been
twenty-five feet long, both previously quite unknown. One more curious
thing about Zeuglodon bones remains to be told, and then we are done
with him; ordinarily a fossil bone will break indifferently in any
direction, but the bones of Zeuglodon are built, like an onion, of
concentric layers, and these have a great tendency to peel off during
the preparation of a specimen.
* * * * *
And now, as the wheels of time and change rolled slowly on, sharks again
came uppermost, and the warmer Eocene and Miocene oceans appear to have
fairly teemed with these sea wolves. There were small sharks with
slender teeth for catching little fishes, there were larger sharks with
saw-like teeth for cutting slices out of larger fishes, and there were
sharks that might almost have swallowed the biggest fish of to-day
whole, sharks of a size the waters had never before contained, and
fortunately do not contain now. We know these monsters mostly by their
teeth, for their skeletons were cartilaginous, and this absence of their
remains is probably the reason why these creatures are passed by while
the adjectives huge, immense, enormous are lavished on the Mosasaurs and
Plesiosaurs--animals that the great-toothed shark, _Carcharodon
megalodon_, might well have eaten at a meal. For the gaping jaws of one
of these sharks, with its hundreds of gleaming teeth must, at a moderate
estimate, have measured not less than six feet across.
The great White Shark, the man-eater, so often found in story books, so
rarely met with in real life, attains a length of thirty feet, and a man
just makes him a good, satisfactory lunch. Now a tooth of this shark is
an inch and a quarter long, while a tooth of the huge _Megalodon_ is
commonly three, often four, and not infrequently five inches long.
Applying the rule of three to such a tooth as this would give a shark
120 feet long, bigger than most whales, to whom a man would be but a
mouthful, just enough to whet his sharkship's appetite. Even granting
that the rule of three unduly magnifies the dimensions of the brute, and
making an ample reduction, there would still remain a fish between
seventy-five and one hundred feet long, quite large enough to satisfy
the most ambitious of _tuna_ fishers, and to have made bathing in the
Miocene ocean unpopular. Contemporary with the great-toothed shark was
another and closely related species that originated with him in Eocene
times, and these two may possibly have had something to do with the
extinction of Zeuglodon. This species is distinguished by having on
either side of the base of the great triangular cutting teeth a little
projection or cusp, like the "ear" on a jar, so that this species has
been named _auriculatus_, or eared. The edges of the teeth are also more
saw-like than in those of its greater relative, and as the species must
have attained a length of fifty or sixty feet it may, with its better
armature, have been quite as formidable. And, as perhaps the readers of
these pages may know, the supply of teeth never ran short. Back of each
tooth, one behind another arranged in serried ranks, lay a reserve of
six or seven smaller, but growing teeth, and whenever a tooth of the
front row was lost, the tooth immediately behind it took its place, and
like a well-trained soldier kept the front line unbroken. Thus the teeth
of sharks are continually developing at the back, and all the teeth are
steadily pushing forward, a very simple mechanical arrangement causing
the teeth to lie flat until they reach the front of the jaw and come
into use.
Once fairly started in life, these huge sharks spread themselves
throughout the warm seas of the world, for there was none might stand
before them and say nay. They swarmed along our southern coast, from
Maryland to Texas; they swarmed everywhere that the water was
sufficiently warm, for their teeth occur in Tertiary strata in many
parts of the world, and the deep-sea dredges of the Challenger and
Albatross have brought up their teeth by scores. And then--they
perished, perished as utterly as did the hosts of Sennacherib. Why? We
do not know. Did they devour everything large enough to be eaten
throughout their habitat, and then fall to eating one another? Again, we
do not know. But perish they did, while the smaller white shark, which
came into being at the same time, still lives, as if to emphasize the
fact that it is best not to overdo things, and that in the long run the
victory is not _always_ to the largest.
_REFERENCES_
_The finest Mosasaur skeleton ever discovered, an almost complete
skeleton of Tylosaurus dyspelor, 29 feet in length, may be seen at the
head of the staircase leading to the Hall of Paleontology, in the
American Museum of Natural History, New York. Another good specimen may
be seen in the Yale University Museum, which probably has the largest
collection of Mosasaurs in existence. Another fine collection is in the
Museum of the State University of Kansas, at Lawrence._
_The best Zeuglodon, the first to show the vestigial hind legs and to
make clear other portions of the structure, is in the United States
National Museum._
_The great sharks are known in this country by their teeth only, and, as
these are common in the phosphate beds, specimens may be seen in
almost any collection. In the United States National Museum, the jaws of
a twelve-foot blue shark are shown for comparison. The largest tooth in
that collection is 5-3/4 inches high and 5 inches across the base. It
takes five teeth of the blue shark to fill the same number of inches._
_The Mosasaurs are described in detail by Professor S. W. Williston, in
Vol. IV. of the "University Geological Survey of Kansas." There is a
technical--and, consequently, uninteresting--account of Zeuglodon in
Vol. XXIII. of the "Proceedings of the United States National Museum,"
page 327._
[Illustration: Fig. 12.--A Tooth of Zeuglodon, one of the "Yoke Teeth,"
from which it derives the name.]
V
BIRDS OF OLD
"_With head, hands, wings, or feet, pursues his way,
And swims, or sinks, or wades, or creeps, or flies._"
When we come to discuss the topic of the earliest bird--not the one in
the proverb--our choice of subjects is indeed limited, being restricted
to the famous and oft-described Archæopteryx from the quarries of
Solenhofen, which at present forms the starting-point in the history of
the feathered race. Bird-like, or at least feathered, creatures, must
have existed before this, as it is improbable that feathers and flight
were acquired at one bound, and this lends probability to the view that
at least some of the tracks in the Connecticut Valley are really the
footprints of birds. Not birds as we now know them, but still creatures
wearing feathers, these being the distinctive badge and livery of the
order. For we may well speak of the feathered race, the exclusive
prerogative of the bird being not flight but feathers; no bird is
without them, no other creature wears them, so that birds may be exactly
defined in two words, feathered animals. Reptiles, and even mammals, may
go quite naked or cover themselves with a defensive armor of bony plates
or horny scales; but under the blaze of the tropical sun or in the chill
waters of arctic seas birds wear feathers only, although in the penguins
the feathers have become so changed that their identity is almost lost.
[Illustration: Fig. 13.--Archæopteryx, the Earliest Known Bird. _From
the specimen in the Berlin Museum._]
So far as flight goes, there is one entire order of mammals, whose
members, the bats, are quite as much at home in the air as the birds
themselves, and in bygone days the empire of the air belonged to the
pterodactyls; even frogs and fishes have tried to fly, and some of the
latter have nearly succeeded in the attempt. As for wings, it may be
said that they are made on very different patterns in such animals as
the pterodactyl, bat, and bird, and that while the end to be achieved is
the same, it is reached by very different methods. The wing membrane of
a bat is spread between his out-stretched fingers, the thumb alone
being left free, while in the pterodactyl the thumb is wanting and the
membrane supported only by what in us is the little finger, a term that
is a decided misnomer in the case of the pterodactyl. In birds the
fingers have lost their individuality, and are modified for the
attachment or support of the wing feathers, but in Archæopteryx the hand
had not reached this stage, for the fingers were partly free and tipped
with claws.
[Illustration: Fig. 14.--Nature's Four Methods of Making a Wing. Bat,
Pterodactyl, Archæopteryx, and Modern Bird.]
We get some side lights on the structure of primitive birds by studying
the young and the earlier stages of living species, for in a very
general way it may be said that the development of the individual is a
sort of rough sketch or hasty outline of the development of the class of
which it is a member; thus the transitory stages through which the chick
passes before hatching give us some idea of the structure of the adult
birds or bird-like creatures of long ago. Now, in embryonic birds the
wing ends in a sort of paw and the fingers are separate, quite different
from what they become a little later on, and not unlike their condition
in Archæopteryx, and even more like what is found in the wing of an
ostrich.
Then, too, there are a few birds still left, such as the ostrich, that
have not kept pace with the others, and are a trifle more like reptiles
than the vast majority of their relatives, and these help a little in
explaining the structure of early birds. Among these is a queer bird
with a queer name, Hoactzin, found in South America, which when young
uses its little wings much like legs, just as we may suppose was done by
birds of old, to climb about the branches. Mr. Quelch, who has studied
these curious birds in their native wilds of British Guiana, tells us
that soon after hatching, the nestlings begin to crawl about by means of
their legs and wings, the well-developed claws on the thumb and finger
being constantly in use for hooking to surrounding objects. If they are
drawn from the nest by means of their legs, they hold on firmly to the
twigs, both with their bill and wings; and if the nest be upset they
hold on to all objects with which they come in contact by bill, feet,
and wings, making considerable use of the bill, with the help of the
clawed wings, to raise themselves to a higher level.
[Illustration: Fig. 15.--Young Hoactzins.]
Thus, by putting these various facts together we obtain some pretty good
ideas regarding the appearance and habits of the first birds. The
immediate ancestors of birds, their exact point of departure from other
vertebrates, is yet to be discovered; at one time it was considered that
they were the direct descendants of Dinosaurs, or that at least both
were derived from the same parent forms, and while that view was almost
abandoned, it is again being brought forward with much to support it. It
has also been thought that birds and those flying reptiles, the
pterodactyls, have had a common ancestry, and the possibility of this is
still entertained. Be that as it may, it is safe to consider that back
in the past, earlier than the Jurassic, were creatures neither bird nor
reptile, but possessing rudimentary feathers and having the promise of a
wing in the structure of their fore legs, and some time one of these
animals may come to light; until then Archæopteryx remains the earliest
known bird.
In the Jurassic, then, when the Dinosaurs were the lords of the earth
and small mammals just beginning to appear, we come upon traces of
full-fledged birds. The first intimation of their presence was the
imprint of a single feather found in that ancient treasure-house, the
Solenhofen quarries; but as Hercules was revealed by his foot, so the
bird was made evident by the feather whose discovery was announced
August 15, 1861. And a little later, in September of the same year, the
bird itself turned up, and in 1877 a second specimen was found, the two
representing two species, if not two distinct genera. These were very
different from any birds now living--so different, indeed, and bearing
such evident traces of their reptilian ancestry, that it is necessary to
place them apart from other animals in a separate division of the class
birds.
Archæopteryx was considerably smaller than a crow, with a stout little
head armed with sharp teeth (as scarce as hens' teeth was no joke in
that distant period), while as he fluttered through the air he trailed
after him a tail longer than his body, beset with feathers on either
side. Everyone knows that nowadays the feathers of a bird's tail are
arranged like the sticks of a fan, and that the tail opens and shuts
like a fan. But in Archæopteryx the feathers were arranged in pairs, a
feather on each side of every joint of the tail, so that on a small
scale the tail was something like that of a kite; and because of this
long, lizard-like tail this bird and his immediate kith and kin are
placed in a group dubbed Saururæ, or lizard tailed.
Because impressions of feathers are not found all around these specimens
some have thought that they were confined to certain portions of the
body--the wings, tail, and thighs--the other parts being naked. There
seems, however, no good reason to suppose that such was the case, for it
is extremely improbable that such perfect and important feathers as
those of the wings and tail should alone have been developed, while
there are many reasons why the feathers of the body might have been lost
before the bird was covered by mud, or why their impressions do not
show.
It was a considerable time after the finding of the first specimen that
the presence of teeth in the jaws was discovered, partly because the
British Museum specimen was imperfect,[6] and partly because no one
suspected that birds had ever possessed teeth, and so no one ever looked
for them. When, in 1877, a more complete example was found, the
existence of teeth was unmistakably shown; but in the meantime, in
February, 1873, Professor Marsh had announced the presence of teeth in
Hesperornis, and so to him belongs the credit of being the discoverer of
birds with teeth.
[6] _The skull was lacking, and a part of the upper jaw lying to one
side was thought to belong to a fish._
The next birds that we know are from our own country, and although
separated by an interval of thousands of years from the Jurassic
Archæopteryx, time enough for the members of one group to have quite
lost their wings, they still retain teeth, and in this respect the most
bird-like of them is quite unlike any modern bird. These come from the
chalk beds of western Kansas, and the first specimens were obtained by
Professor Marsh in his expeditions of 1870 and 1871, but not until a few
years later, after the material had been cleaned and was being studied,
was it ascertained that these birds were armed with teeth. The smaller
of these birds, which was apparently not unlike a small gull in general
appearance, was, saving its teeth, so thoroughly a bird that it may be
passed by without further notice, but the larger was remarkable in many
ways. Hesperornis, the western bird, was a great diver, in some ways the
greatest of the divers, for it stood higher than the king penguin,
though more slender and graceful in general build, looking somewhat like
an overgrown, absolutely wingless loon.
The penguins, as everyone knows, swim with their front limbs--we can't
call them wings--which, though containing all the bones of a wing, have
become transformed into powerful paddles; Hesperornis, on the other
hand, swam altogether with its legs--swam so well with them, indeed,
that through disuse the wings dwindled away and vanished, save one bone.
This, however, is not stating the theory quite correctly; of course the
matter cannot be actually proved. Hesperornis was a large bird, upwards
of five feet in length, and if its ancestors were equally bulky their
wings were quite too large to be used in swimming under water, as are
those of such short-winged forms as the Auks which fly under the water
quite as much as they fly over it. Hence the wings were closely folded
upon the body so as to offer the least possible resistance, and being
disused, they and their muscles dwindled, while the bones and muscles
of the legs increased by constant use. By the time the wings were small
enough to be used in so dense a medium as water the muscles had become
too feeble to move them, and so degeneration proceeded until but one
bone remained, a mere vestige of the wing that had been. The penguins
retain their great breast muscles, and so did the Great Auk, because
their wings are used in swimming, since it requires even more strength
to move a small wing in water than it does to move a large wing in the
thinner air. As for our domesticated fowls--the turkeys, chickens, and
ducks--there has not been sufficient lapse of time for their muscles to
dwindle, and besides artificial selection, the breeding of fowls for
food has kept up the mere size of the muscles, although these lack the
strength to be found in those of wild birds.
As a swimming bird, one that swims with its legs and not with its wings,
Hesperornis has probably never been equalled, for the size and
appearance of the bones indicate great power, while the bones of the
foot were so joined to those of the leg as to turn edgewise as the foot
was brought forward and thus to offer the least possible resistance to
the water. It is a remarkable fact that the leg bones of Hesperornis are
hollow, remarkable because as a rule the bones of aquatic animals are
more or less solid, their weight being supported by the water; but those
of the great diver were almost as light as if it had dwelt upon the dry
land. That it did not dwell there is conclusively shown by its build,
and above all by its feet, for the foot of a running bird is modified in
quite another way.
The bird was probably covered with smooth, soft feathers, something like
those of an Apteryx; this we know because Professor Williston found a
specimen showing the impression of the skin of the lower part of the leg
as well as of the feathers that covered the "thigh" and head. While such
a covering seems rather inadequate for a bird of such exclusively
aquatic habits as Hesperornis must have been, there seems no getting
away from the facts in the case in the shape of Professor Williston's
specimen, and we have in the Snake Bird, one of the most aquatic of
recent birds, an instance of similarly poor covering. As all know who
have seen this bird at home, its feathers shed the water very
imperfectly, and after long-continued submersion become saturated, a
fact which partly accounts for the habit the bird has of hanging itself
out to dry.
[Illustration: Fig. 16.--Hesperornis, the Great Toothed Diver. _From a
drawing by J. M. Gleeson._]
The restoration which Mr. Gleeson has drawn differs radically from any
yet made, and is the result of a careful study of the specimen belonging
to the United States National Museum. No one can appreciate the
peculiarities of Hesperornis and its remarkable departures from other
swimming birds who has not seen the skeleton mounted in a swimming
attitude. The great length of the legs, their position at the middle of
the body, the narrowness of the body back of the hip joint, and the
disproportionate length of the outer toe are all brought out in a manner
which a picture of the bird squatting upon its haunches fails utterly to
show. As for the tail, it is evident from the size and breadth of the
bones that something of the kind was present; it is also evident that it
was not like that of an ordinary bird, and so it has been drawn with
just a suggestion of Archæopteryx about it.
The most extraordinary thing about Hesperornis, however, is the position
of the legs relative to the body, and this is something that was not
even suspected until the skeleton was mounted in a swimming attitude. As
anyone knows who has watched a duck swim, the usual place for the feet
and legs is beneath and in a line with the body. But in our great
extinct diver the articulations of the leg bones are such that this is
impossible, and the feet and lower joint of the legs (called the tarsus)
must have stood out nearly at right angles to the body, like a pair of
oars. This is so peculiar and anomalous an attitude for a bird's legs
that, although apparently indicated by the shape of the bones, it was at
first thought to be due to the crushing and consequent distortion to
which the bones had been subjected, and an endeavor was made to place
the legs in the ordinary position, even though this was done at the
expense of some little dislocation of the joints. But when the mounting
of the skeleton had advanced further it became more evident that
Hesperornis was not an ordinary bird, and that he could not have swum in
the usual manner, since this would have brought his great knee-caps up
into his body, which would have been uncomfortable. And so, at the cost
of some little time and trouble,[7] the mountings were so changed that
the legs stood out at the sides of the body, as shown in the picture.
[7] _The mounting of fossil bones is quite a different matter from the
wiring of an ordinary skeleton, since the bones are not only so hard
that they cannot be bored and wired like those of a recent animal, but
they are so brittle and heavy that often they will not sustain their own
weight. Hence such bones must be supported from the outside, and to do
this so that the mountings will be strong enough to support their
weight, allow the bones to be removed for study, and yet be
inconspicuous, is a difficult task._
A final word remains to be said about toothed birds, which is, that the
visitor who looks upon one for the first time will probably be
disappointed. The teeth are so loosely implanted in the jaw that most of
them fall out shortly after death, while the few that remain are so
small as not to attract observation.
By the time the Eocene Period was reached, even before that, birds had
become pretty much what we now see them, and very little change has
taken place in them since that time; they seem to have become so exactly
adapted to the conditions of existence that no further modification has
taken place. This may be expressed in another way, by saying that while
the Mammals of the Eocene have no near relatives among those now living,
entire large groups having passed completely out of existence, the few
birds that we know might, so far as their appearance and affinities go,
have been killed yesterday.
Were we to judge of the former abundance of birds by the number we find
in a fossil state, we should conclude that in the early days of the
world they were remarkably scarce, for bird bones are among the rarest
of fossils. But from the high degree of development evidenced by the few
examples that have come to light, and the fact that these represent
various and quite distinct species,[8] we are led to conclude that
birds were abundant enough, but that we simply do not find them.
[8] _But three birds, besides a stray feather or two, are so far known
from the Eocene of North America. One of these is a fowl not very unlike
some of the small curassows of South America; another is a little bird,
supposed to be related to the sparrows, while the third is a large bird
of uncertain relationships._
Several eggs, too--or, rather, casts of eggs--have lately been found in
the Cretaceous and Miocene strata of the West; and, as eggs and birds
are usually associated, we are liable at any time to come upon the bones
of the birds that laid them.
To the writer's mind no thoroughly satisfactory explanation has been
given for the scarcity of bird remains; but the reason commonly advanced
is that, owing to their lightness, dead birds float for a much longer
time than other animals, and hence are more exposed to the ravages of
the weather and the attacks of carrion-feeding animals. It has also been
said that the power of flight enabled birds to escape calamities that
caused the death of contemporary animals; but all birds do not fly; and
birds do fall victims to storms, cold, and starvation, and even perish
of pestilence, like the Cormorants of Bering Island, whose ranks have
twice been decimated by disease.
It is true that where carnivorous animals abound, dead birds do
disappear quickly; and my friend Dr. Stejneger tells me that, while
hundreds of dead sea-fowl are cast on the shores of the Commander
Islands, it is a rare thing to find one after daylight, as the bodies
are devoured by the Arctic foxes that prowl about the shores at night.
But, again, as in the Miocene of Southern France and in the Pliocene of
Oregon, remains of birds are fairly numerous, showing that, under proper
conditions, their bones are preserved for future reference, so that we
may hope some day to come upon specimens that will enable us to round
out the history of bird life in the past.
_REFERENCES_
_The first discovered specimen of Archæopteryx, Archæopteryx macrura, is
in the British Museum, the second more complete example is in the Royal
Museum of Natural History, Berlin. The largest collection of toothed
birds, including the types of Hesperornis, Ichthyornis and others, is in
the Yale University Museum, at New Haven. The United States National
Museum at Washington has a fine mounted skeleton of Hesperornis, and the
State University of Kansas, at Lawrence, has the example showing the
impressions of feathers._
_For scientific descriptions of these birds the reader is referred to
Owen's paper "On the Archæopteryx of von Meyer, with a Description of
the Fossil Remains, etc.," in the "Transactions of the Philosophical
Society of London for 1863," page 33, and "Odontornithes, a Monograph of
the Extinct Toothed Birds of North America," by O. C. Marsh. Much
popular and scientific information concerning the early birds is to be
found in Newton's "Dictionary of Birds," and "The Story of Bird Life,"
by W. P. Pycraft; the "Structure and Life of Birds," by F. W. Headley;
"The Story of the Birds," by J. Newton Baskett._
[Illustration: Fig. 17.--Archæopteryx as Restored by Mr. Pycraft.]
VI
THE DINOSAURS
"_Shapes of all sorts and sizes, great and small._"
A few million years ago, geologists and physicists do not agree upon the
exact number, although both agree upon the millions, when the Rocky
Mountains were not yet born and the now bare and arid western plains a
land of lakes, rivers, and luxuriant vegetation, the region was
inhabited by a race of strange and mighty reptiles upon whom science has
bestowed the appropriate name of Dinosaurs, or terrible lizards.
Our acquaintance with the Dinosaurs is comparatively recent, dating from
the early part of the nineteenth century, and in America, at least, the
date may be set at 1818, when the first Dinosaur remains were found in
the Valley of the Connecticut, although they naturally were not
recognized as such, nor had the term been devised. The first Dinosaur
to be formally recognized as representing quite a new order of reptiles
was the carnivorous Megalosaur, found near Oxford, England, in 1824.
[Illustration: Fig. 18.--Thespesius. A Common Herbivorous Dinosaur of
the Cretaceous. _From a drawing by Charles R. Knight._]
For a long time our knowledge of Dinosaurs was very imperfect and
literally fragmentary, depending mostly upon scattered teeth, isolated
vertebræ, or fragments of bone picked up on the surface or casually
encountered in some mine or quarry. Now, however, thanks mainly to the
labors of American palæontologists, thanks also to the rich deposits of
fossils in our Western States, we have an extensive knowledge of the
Dinosaurs, of their size, structure, habits, and general appearance.
There are to-day no animals living that are closely related to them;
none have lived for a long period of time, for the Dinosaurs came to an
end in the Cretaceous, and it can only be said that the crocodiles, on
the one hand, and the ostriches, on the other, are the nearest existing
relatives of these great reptiles.
For, though so different in outward appearance, birds and reptiles are
structurally quite closely allied, and the creeping snake and the bird
on which it preys are relatives, although any intimate relationship
between them is of the serpent's making, and is strongly objected to by
the bird.
But if we compare the skeleton of a Dinosaur with that of an ostrich--a
young one is preferable--and with those of the earlier birds, we shall
find that many of the barriers now existing between reptiles and birds
are broken down, and that they have many points in common. In fact, save
in the matter of clothes, wherein birds differ from all other animals,
the two great groups are not so very far apart.
The Dinosaurs were by no means confined to North America, although the
western United States seem to have been their headquarters, but ranged
pretty much over the world, for their remains have been found in every
continent, even in far-off New Zealand.
In point of time they ranged from the Trias to the Upper Cretaceous,
their golden age, marking the culminating point of reptilian life, being
in the Jurassic, when huge forms stalked by the sea-shore, browsed amid
the swamps, or disported themselves along the reedy margins of lakes
and rivers.
They had their day, a day of many thousand years, and then passed away,
giving place to the superior race of mammals which was just springing
into being when the huge Dinosaurs were in the heyday of their
existence.
And it does seem as if in the dim and distant past, as in the present,
brains were a potent factor in the struggle for supremacy; for, though
these reptiles were giants in size, dominating the earth through mere
brute force, they were dwarfs in intellect.
The smallest human brain that is thought to be compatible with life
itself weighs a little over ten ounces, the smallest that can exist with
reasoning powers is two pounds; this in a creature weighing from 120 to
150 pounds.
What do we find among Dinosaurs? Thespesius, or Claosaurus, which may
have walked where Baltimore now stands, was twenty-five feet in length
and stood a dozen feet high in his bare feet, had a brain smaller than a
man's clenched fist, weighing less than one pound.
Brontosaurus, in some respects the biggest brute that ever walked, was
but little better off, and Triceratops, and his relatives, creatures
having twice the bulk of an elephant, weighing probably over ten tons,
possessed a brain weighing not over two pounds!
How much of what we term intelligence could such a creature
possess--what was the extent of its reasoning powers? Judging from our
own standpoint and the small amount of intellect apparent in some humans
with much larger brains, these big reptiles must have known just about
enough to have eaten when they were hungry, anything more was
superfluous.
However, intelligence is one thing, life another, and the spinal cord,
with its supply of nerve-substance, doubtless looked after the mere
mechanical functions of life; and while even the spinal cord is in many
cases quite small, in some places, particularly in the sacral region, it
is subject to considerable enlargement. This is notably true of
Stegosaurus, where the sacral enlargement is twenty times the bulk of
the puny brain--a fact noted by Professor Marsh, and seized upon by the
newspapers, which announced that he had discovered a Dinosaur with a
brain in its pelvis.
In their great variety of size and shape the Dinosaurs form an
interesting parallel with the Marsupials of Australia. For just as these
are, as it were, an epitome of the class of mammals, mimicking the
herbivores, carnivores, rodents and even monkeys, so there are
carnivorous and herbivorous Dinosaurs--Dinosaurs that dwelt on land and
others that habitually resided in the water, those that walked upright
and those that crawled about on all fours; and, while there are no hints
that any possessed the power of flight, some members of the group are
very bird-like in form and structure, so much so that it has been
thought that the two may have had a common ancestry.
The smallest of the Dinosaurs whose acquaintance we have made were
little larger than chickens; the largest claim the distinction of being
the largest known quadrupeds that have walked the face of the earth, the
giants not only of their day, but of all time, before whose huge frames
the bones of the Mammoth, that familiar byword for all things great,
seem slight.
For Brontosaurus, the Thunder Lizard, beneath whose mighty tread the
earth shook, and his kindred were from 40 to 60 feet long and 10 to 14
feet high, their thigh bones measuring 5 to 6 feet in length, being the
largest single bones known to us, while some of the vertebræ were 4-1/2
feet high, exceeding in dimensions those of a whale.
[Illustration: Fig. 19--A Hind Leg of the Great Brontosaurus, the
Largest of the Dinosaurs.]
The group to which Brontosaurus belongs, including Diplodocus and
Morosaurus, is distinguished by a large, though rather short, body,
very long neck and tail, and, for the size of the animal, a very small
head. In fact, the head was so small and, in the case of Diplodocus, so
poorly provided with teeth that it must have been quite a task, or a
long-continued pleasure, according to the state of its digestive
apparatus, for the animal to have eaten its daily meal.
[Illustration: Fig. 20.--A Single Vertebra of Brontosaurus.]
An elephant weighing 5 tons eats 100 pounds of hay and 25 pounds of
grain for his day's ration; but, as this food is in a comparatively
concentrated form, it would require at least twice this weight of green
fodder.
It is a difficult matter to estimate the weight of a live Diplodocus or
a Brontosaurus, but it is pretty safe to say that it would not be far
from 20 tons, and that one would devour at the very least something over
700 pounds of leaves or twigs or plants each day--more, if the animal
felt really hungry.
But here we must, even if reluctantly, curb our imagination a little and
consider another point: the cold-blooded, sluggish reptiles, as we know
them to-day, do not waste their energies in rapid movements, or in
keeping the temperature of their bodies above that of the air, and so by
no means require the amount of food needed by more active, warm-blooded
animals. Alligators, turtles, and snakes will go for weeks, even months,
without food, and while this applies more particularly to those that
dwell in temperate climes and during their winter hibernation
practically suspend the functions of digestion and respiration, it is
more or less true of all reptiles. And as there is little reason for
supposing that reptiles behaved in the past any differently from what
they do in the present, these great Dinosaurs may, after all, not have
been gifted with such ravenous appetites as one might fancy. Still, it
is dangerous to lay down any hard and fast laws concerning animals, and
he who writes about them is continually obliged to qualify his
remarks--in sporting parlance, to hedge a little, and in the present
instance there is some reason, based on the arrangement of vertebræ and
ribs, to suppose that the lungs of Dinosaurs were somewhat like those of
birds, and that, as a corollary, their blood may have been better
aërated and warmer than that of living reptiles. But, to return to the
question of food.
From the peculiar character of the articulations of the limb-bones, it
is inferred that these animals were largely aquatic in their habits, and
fed on some abundant species of water plants. One can readily see the
advantage of the long neck in browsing off the vegetation on the bottom
of shallow lakes, while the animal was submerged, or in rearing the head
aloft to scan the surrounding shores for the approach of an enemy. Or,
with the tail as a counterpoise, the entire body could be reared out of
water and the head be raised some thirty feet in the air.
Triceratops, he of the three-horned face, had a remarkable skull which
projected backward over the neck, like a fireman's helmet, or a
sunbonnet worn hind side before, while over each eye was a massive horn
directed forward, a third, but much smaller horn being sometimes present
on the nose.
The little "Horned Toad," which isn't a toad at all, is the nearest
suggestion we have to-day of Triceratops; but, could he realize the
ambition of the frog in the fable and swell himself to the dimensions of
an ox, he would even then be but a pigmy compared with his ancient and
distant relative.
So far as mere appearance goes he would compare very well, for while so
much is said about the strange appearance of the Dinosaurs, it is to be
borne in mind that their peculiarities are enhanced by their size, and
that there are many lizards of to-day that lack only stature to be even
more _bizarre_; and, for example, were the Australian Moloch but big
enough, he could give even Stegosaurus "points" in more ways than one.
Standing before the skull of Triceratops, looking him squarely in the
face, one notices in front of each eye a thick guard of projecting bone,
and while this must have interfered with vision directly ahead it must
have also furnished protection for the eye. So long as Triceratops faced
an adversary he must have been practically invulnerable, but as he was
the largest animal of his time, upward of twenty-five feet in length, it
is probable that his combats were mainly with those of his own kind and
the subject of dispute some fair female upon whom two rival suitors had
cast covetous eyes. What a sight it would have been to have seen two of
these big brutes in mortal combat as they charged upon each other with
all the impetus to be derived from ten tons of infuriate flesh! We may
picture to ourselves horn clashing upon horn, or glancing from each bony
shield until some skilful stroke or unlucky slip placed one combatant at
the mercy of the other, and he went down before the blows of his
adversary "as falls on Mount Alvernus a thunder-smitten oak."
[Illustration: Fig. 21.--Moloch. A Modern Lizard that Surpasses the
Stegosaurs in All but Size. _From a drawing by J. M. Gleeson._]
A pair of Triceratops horns in the National Museum bears witness to such
encounters, for one is broken midway between tip and base; and that it
was broken during life is evident from the fact that the stump is healed
and rounded over, while the size of the horns shows that their owner
reached a ripe old age.
For, unlike man and the higher vertebrates, reptiles and fishes do not
have a maximum standard of size which is soon reached and rarely
exceeded, but continue to grow throughout life, so that the size of a
turtle, a crocodile, or a Dinosaur tells something of the duration of
its life.
Before quitting Triceratops let us glance for a moment at its skeleton.
Now among other things a skeleton is the solution of a problem in
mechanics, and in Triceratops the head so dominates the rest of the
structure that one might almost imagine the skull was made first and the
body adjusted to it. The great head seems made not only for offence and
defence; the spreading frill serves for the attachment of muscles to
sustain the weight of the skull, while the work of the muscles is made
easier by the fact that the frill reaches so far back of the junction of
head with neck as to largely counterbalance the weight of the face and
jaws. When we restored the skull of this animal it was found that the
centre of gravity lay back of the eye. Several of the bones of the neck
are united in one mass to furnish a firm attachment for the muscles that
support and move the skull, but as the movements of the neck are already
restricted by the overhanging frill, this loss of motion is no
additional disadvantage.
[Illustration: TRICERATOPS PRORSUS Marsh Fig. 22.--Skeleton of
Triceratops.]
To support all this weight of skull and body requires very massive
legs, and as the fore legs are very short, this enables Triceratops to
browse comfortably from the ground by merely lowering the front of the
head.
These forms we have been considering were the giants of the group, but a
commoner species, Thespesius, though less in bulk than those just
mentioned, was still of goodly proportions, for, as he stalked about,
the top of his head was twelve feet from the ground.
Thespesius and his kin seem to have been comparatively abundant, for
they have a wide distribution, and many specimens, some almost perfect,
have been discovered in this country and abroad. No less than
twenty-nine Iguanodons, a European relative of Thespesius, were found in
one spot in mining for coal at Bernissart, Belgium. Here, during long
years of Cretaceous time, a river slowly cut its way through the
coal-bearing strata to a depth of 750 feet, a depth almost twice as
great as the deepest part of the gorge of Niagara, and then, this being
accomplished, began the work of filling up the valley it had excavated.
It was then a sluggish stream with marshy borders, a stream subject to
frequent floods, when the water, turbid with mud and laden with sand,
overflowed its banks, leaving them, as the waters subsided, covered
thickly with mud. Here, amidst the luxuriant vegetation of a
semi-tropical climate, lived and died the Iguanodons, and here the pick
of the miner rescued them from their long entombment to form part of the
treasures of the museum at Brussels.
Like other reptiles, living and extinct, Thespesius was continually
renewing his teeth, so that as fast as one tooth was worn out it was
replaced by another, a point wherein Thespesius had a decided advantage
over ourselves. On the other hand, as there was a reserve supply of
something like 400 teeth in the lower jaw alone, what an opportunity for
the toothache!
And then we have a multitude of lesser Dinosaurs, including the active,
predatory species with sharp claws and double-edged teeth. Megalosaurus,
the first of the Dinosaurs to be really known, was one of these
carnivorous species, and from our West comes a near relative,
Ceratosaurus, the nose-horned lizard, a queer beast with tiny fore legs,
powerful, sharp-clawed hind feet, and well-armed jaws. A most formidable
foe he seems, the more that the hollow bones speak of active movements,
and Professor Cope pictured him, or a near relative, vigorously engaged
in combat with his fellows, or preying upon the huge but helpless
herbivores of the marshes, leaping, biting, and tearing his enemy to
pieces with tooth and claw.
Professor Osborn, on the other hand, is inclined to consider him as a
reptilian hyena, feeding upon carrion, although one can but feel that
such an armament is not entirely in the interests of peace.
Last, but by no means least, are the Stegosaurs, or plated lizards, for
not only were they beasts of goodly size, but they were among the most
singular of all known animals, singular even for Dinosaurs. They had
diminutive heads, small fore legs, long tails armed on either side near
the tip, with two pairs of large spines, while from these spines to the
neck ran series of large, but thin, and sharp-edged plates standing
on edge, so that their backs looked like the bottom of a boat provided
with a number of little centreboards. Just how these plates were
arranged is not decided beyond a peradventure, but while originally
figured as having them in a single series down the back it seems much
more probable that they formed parallel rows.
[Illustration: Fig. 23.--The Horned Ceratosaurus. A Carnivorous
Dinosaur. _From a drawing by J. M. Gleeson._]
The largest of these plates were two feet in height and length, and not
more than an inch thick, except at the base, where they were enlarged
and roughened to give a firm hold to the thick skin in which they were
imbedded. Be it remembered, too, that these plates and spines were
doubtless covered with horn, so that they were even longer in life than
as we now see them. The tail spines varied in length, according to the
species, from eight or nine inches to nearly three feet, and some of
them have a diameter of six inches at the base. They were swung by a
tail eight to ten feet long, and as a visitor was heard to remark, one
wouldn't like to be about such an animal in fly time.
Such were some of the strange and mighty animals that once roamed this
continent from the valley of the Connecticut, where they literally left
their footprints on the sands of time, to the Rocky Mountains, where the
ancient lakes and rivers became cemeteries for the entombment of their
bones.
The labor of the collector has gathered their fossil remains from many a
Western canyon, the skill of the preparator has removed them from their
stony sepulchres and the study of the anatomist has restored them as
they were in life.
_REFERENCES._
_Most of our large museums have on exhibition fine specimens of many
Dinosaurs, comprising skulls, limbs, and large portions of their
skeletons. The American Museum of Natural History, New York, has the
largest and finest display. The first actual skeleton of a Dinosaur to
be mounted in this country was the splendid Claosaurus at the Yale
University Museum, where other striking pieces are also to be seen. The
mounting of this Claosaurus, which is 29 feet long and 13 feet high,
took an entire year. The United States National Museum is
particularly rich in examples of the great, horned Triceratops, while
the Carnegie Museum, Pittsburgh, has the best Diplodocus. The Field
Columbian Museum and the Universities of Wyoming and Colorado all have
good collections._
[Illustration: Fig. 24.--Stegosaurus. An Armored Dinosaur of the
Jurassic. _From a drawing by Charles R. Knight._]
_The largest single bone of a Dinosaur is the thigh bone of a
Brontosaurus in the Field Columbian Museum, this measuring 6 feet 8
inches in length. The height of a complete hind leg in the American
Museum of Natural History is 10 feet, while a single claw measures 6 by
9 inches. The skeleton of Triceratops restored in papier-maché for the
Pan-American Exposition measured 25 feet from tip of nose to end of tail
and was 10 feet 6 inches to the top of the backbone over the hips, this
being the highest point. The head in the United States National Museum
used as a model is 5 feet 6 inches long in a straight line and 4 feet 3
inches across the frill. There is a skull in the Yale University Museum
even larger than this._
_Articles relating to Dinosaurs are mostly technical in their nature and
scattered through various scientific journals. The most accessible
probably is "The Dinosaurs of North America," by Professor O. C. Marsh,
published as part of the sixteenth annual report of the United States
Geological Survey. This contains many figures of the skulls, bones, and
entire skeletons of many Dinosaurs._
[Illustration: Fig. 25.--Skull of Ceratosaurus. _From a specimen in the
United States National Museum._]
VII
READING THE RIDDLES OF THE ROCKS
"_And the first Morning of Creation wrote
What the Last Dawn of Reckoning shall read._"
It is quite possible that the reader may wish to know something of the
manner in which the specimens described in these pages have been
gathered, how we acquire our knowledge of Brontosaurus, Claosaurus, or
any of the many other "sauruses," and how their restorations have been
made.
There was a time, not so very long ago, when fossils were looked upon as
mere sports of Nature, and little attention paid to them; later their
true nature was recognized, though they were merely gathered haphazard
as occasion might offer. But now, and for many years past, the
fossil-bearing rocks of many parts of the world have been systematically
worked, and from the material thus obtained we have acquired a great
deal of information regarding the inhabitants of the ancient world. This
is particularly true of our own western country, where a vast amount of
collecting has been done, although very much remains to be done in the
matter of perfecting this knowledge, and hosts of new animals remain to
be discovered. For this information we are almost as much indebted to
the collector who has gathered the needed material, and the preparator
whose patience and skill have made it available for study, as to the
palæontologist who has interpreted the meaning of the bones.
To collect successfully demands not only a knowledge of the rocks in
which fossils occur and of the localities where they are best exposed to
view, but an eye quick to detect a piece of bone protruding from a rock
or lying amongst the shale, and, above all, the ability to work a
deposit to advantage after it has been found. The collector of living
animals hies to regions where there is plenty for bird and beast to eat
and drink, but the collector of extinct animals cares little for what is
on the surface of the earth; his great desire is to see as much as
possible of what may lie beneath. So the prospector in search of fossils
betakes himself to some region where the ceaseless warfare waged by
water against the dry land has seamed the face of the earth with
countless gullies and canyons, or carved it into slopes and bluffs in
which the edges of the bone-bearing strata are exposed to view, and
along these he skirts, ever on the look-out for some projecting bit of
bone. The country is an almost shadeless desert, burning hot by day,
uncomfortably cool at night. Water is scarce, and when it can be found,
often has little to commend it save wetness; but the collector is buoyed
up through all this with the hope that he may discover some creature new
to science that shall not only be bigger and uglier and stranger than
any heretofore found, but shall be the long-sought form needed for the
solution of some difficult problem in the history of the past.
Now collecting is a lottery, differing from most lotteries, however, in
that while some of the returns may be pretty small, there are few
absolute blanks and some remarkably large prizes, and every collector
hopes that it may fall to his lot to win one of these, and is willing to
work long and arduously for the chance of obtaining it.
It may give some idea of the chances to say that some years ago Dr.
Wortman spent almost an entire season in the field without success, and
then, at the eleventh hour, found the now famous skeleton of Phenacodus,
or that a party from Princeton actually camped within 100 yards of a
rich deposit of rare fossils and yet failed to discover it.
Let us, however, suppose that the reconnaissance has been successful,
and that an outcrop of bone has been found, serving like a tombstone
carven with strange characters to indicate the burial-place of some
primeval monster. Possibly Nature long ago rifled the grave, washing
away much of the skeleton, and leaving little save the fragments visible
on the surface; on the other hand, these pieces may form part of a
complete skeleton, and there is no way to decide this important question
save by actual excavation. The manner of disinterment varies, but much
depends on whether the fossil lies in comparatively loose shale or is
imbedded in the solid rock, whether the strata are level or dip downward
into the hillside. If, unfortunately, this last is the case, it
necessitates a careful shoring up of the excavation with props of
cotton-wood or such boards as may have been brought along to box
specimens, or it may even be necessary to run a short tunnel in order to
get at some coveted bone. Should the specimen lie in shale, as is the
case with most of the large reptiles that have been collected, much of
that work may be done with pick and shovel; but if it is desirable or
necessary to work in firm rock, drills and hammers, wedges, even powder,
may be needed to rend from Nature her long-kept secrets. In any event, a
detailed plan is made of the excavation, and each piece of bone or
section of rock duly recorded therein by letter and number, so that
later on the relation of the parts to one another may be known, or the
various sections assembled in the work-room exactly as they lay in the
quarry. Bones which lie in loose rock are often, one might say usually,
more or less broken, and when a bone three, four, or even six feet
long, weighing anywhere from 100 to 1,000 pounds, has been shattered to
fragments the problem of removing it is no easy one. But here the skill
of the collector comes into play to treat the fossil as a surgeon treats
a fractured limb, to cover it with plaster bandages, and brace it with
splints of wood or iron so that the specimen may not only be taken from
the ground but endure in safety the coming journey of a thousand or more
miles. For simpler cases or lighter objects strips of sacking, or even
paper, applied with flour and water, suffice, or pieces of sacking
soaked in thin plaster may be laid over the bone, first covering it with
thin paper in order that the plaster jacket may simply stiffen and not
adhere to it. Collecting has not always been carried on in this
systematic manner, for the development of the present methods has been
the result of years of experience; formerly there was a mere
skimming-over of the surface in what Professor Marsh used to term the
potato-gathering style, but now the effort is made to remove specimens
intact, often imbedded in large masses of rock, in order that all parts
may be preserved.
We will take it for granted that our specimens have safely passed
through all perils by land and water, road and rail; that they have been
quarried, boxed, carted over a roadless country to the nearest railway,
and have withstood 2,000 miles of jolting in a freight-car. The first
step in reconstruction has been taken; the problem, now that the boxes
are reposing on the work-room floor, is to make the blocks of stone give
up the secrets they have guarded for ages, to free the bones from their
enveloping matrix in order that they may tell us something of the life
of the past. The method of doing this varies with the conditions under
which the material has been gathered, and if from hard clay, chalk, or
shale, the process, though tedious enough at best, is by no means so
difficult as if the specimens are imbedded in solid rock. In this case
the fragments from a given section of quarry must be assembled according
to the plan which has been carefully made as the work of exhumation
progressed, all pieces containing bone must be stuck together, and weak
parts strengthened with gum or glue. Now the mass is attacked with
hammer and chisel, and the surrounding matrix slowly and carefully cut
away until the contained bone is revealed, a process much simpler and
more expeditious in the telling than in the actuality; for the
preparator may not use the heavy tools of the ordinary stone-cutter:
sometimes an awl, or even a glover's needle, must suffice him, and the
chips cut off are so small and such care must be taken not to injure the
bone that the work is really tedious. This may, perhaps, be better
appreciated by saying that to clean a single vertebra of such a huge
Dinosaur as Diplodocus may require a month of continuous labor, and that
a score of these big and complicated bones, besides others of simpler
structure, are included in the backbone. The finished specimen weighs
over 120 pounds, while as originally collected, with all the adherent
rock, the weight was twice or thrice as great. Such a mass as this is
comparatively small, and sometimes huge blocks are taken containing
entire skulls or a number of bones, and not infrequently weighing a
ton. The largest single specimen is a skull of Triceratops, collected by
Mr. J. B. Hatcher, which weighed, when boxed, 3,650 pounds.
Or, as the result of some mishap, or through the work of an
inexperienced collector, a valuable specimen may arrive in the shape of
a box full of irregular fragments of stone compared with which a
dissected map or an old-fashioned Chinese puzzle is simplicity itself,
and one may spend hours looking for some piece whose proper location
gives the clew to an entire section, and days, even, may be consumed
before the task is completed. While this not only tries the patience,
but the eyes as well, there is, nevertheless, a fascination about this
work of fashioning a bone out of scores, possibly hundreds, of
fragments, and watching the irregular bits of stone shaping themselves
into a mosaic that forms a portion of some creature, possibly quite new
to science, and destined to bear a name as long as itself. And thus,
after many days of toil, the bone that millions of years before sank
into the mud of some old lake-bottom or was buried in the sandy shoals
of an ancient river, is brought to light once more to help tell the tale
of the creatures of the past.
One bone might convey a great deal of information; on the other hand it
might reveal very little; for, while it is very painful to say so, the
popular impression that it is possible to reconstruct an animal from a
single bone, or tell its size and habits from a tooth is but partially
correct, and sometimes "the eminent scientist" has come to grief even
with a great many bones at his disposal. Did not one of the ablest
anatomists describe and figure the hip-bones of a Dinosaur as its
shoulder-blade, and another, equally able, reconstruct a reptile "hind
side before," placing the head on the tail! This certainly sounds absurd
enough; but just as absurd mistakes are made by men in other walks of
life, often with far more deplorable results.
Before passing to the restoration of the exterior of animals it may be
well to say something of the manner in which the skeleton of an extinct
animal may be reconstructed and the meaning of its various parts
interpreted. For the adjustment of the muscles is dependent on the
structure of the skeleton, and putting on the muscles means blocking out
the form, details of external appearance being supplied by the skin and
its accessories of hair, scales, or horns. Let us suppose in the present
instance that we are dealing with one of the great reptiles known as
Triceratops whose remains are among the treasures of the National Museum
at Washington, for the reconstruction of the big beast well illustrates
the methods of the palæontologist and also the troubles by which he is
beset. Moreover, this is not a purely imaginary case, but one that is
very real, for the skeleton of this animal which was shown at Buffalo
was restored in papier-maché in exactly the manner indicated. We have a
goodly number of bones, but by no means an entire skeleton, and yet we
wish to complete the skeleton and incidentally to form some idea of the
creature's habits. Now we can interpret the past only by a knowledge of
the present, and it is by carefully studying the skeletons of the
animals of to-day that we can learn to read the meaning of the symbols
of bones left by the animals of a million yesterdays. Thus we find that
certain characters distinguish the bone of a mammal from that of a bird,
a reptile, or a fish, and these in turn from one another, and this
constitutes the A B C of comparative anatomy. And, in a like manner, the
bones of the various divisions of these main groups have to a greater or
less extent their own distinguishing characteristics, so that by first
comparing the bones of extinct animals with those of creatures that are
now living we are enabled to recognize their nearest existing relative,
and then by comparing them with one another we learn the relations they
bore in the ancient world. But it must be borne in mind that some of the
early beasts were so very different from those of to-day that until
pretty much their entire structure was known there was nothing with
which to compare odd bones. Had but a single incomplete specimen of
Triceratops come to light we should be very much in the dark concerning
him; and although remains of some thirty individuals have been
discovered, these have been so imperfect that we are very far from
having all the information we need. A great part of the head, with its
formidable looking horns, is present, and although the nose is gone, we
know from other specimens that it, too, was armed with a knob, or horn,
and that the skull ended in a beak, something like that of a snapping
turtle, though formed by a separate and extra bone; similarly the end of
the lower jaw is lacking, but we may be pretty certain that it ended in
a beak, to match that of the skull. The large leg-bones of our specimen
are mostly represented, for these being among the more solid parts of
the skeleton are more frequently preserved than any others, and though
some are from one side and some from another, this matters not. If the
hind legs were disproportionately long it would indicate that our animal
often or habitually walked erect, but as there is only difference enough
between the fore and hind limbs to enable Triceratops to browse
comfortably from the ground we would naturally place him on all fours,
even were the skull not so large as to make the creature too top-heavy
for any other mode of locomotion. Were the limbs very small in
comparison with the other bones, it would obviously mean that their
owner passed his life in the water. For a skeleton has a twofold
meaning, it is the best, the most enduring, testimony we have as to an
animal's place in nature and the relationships it sustains to the
creatures that lived with it, before it, and after it. More than this, a
skeleton is the solution of a problem in mechanics, the problem of
carrying a given weight and of adaptation to a given mode of life. Thus
the skeleton varies according as a creature dwells on land, in the
water, or in the air, and according as it feeds on grass or preys upon
its fellows.
And so the mechanics of a skeleton afford us a clew to the habits of the
living animal. Something, too, may be gathered from the structure of the
leg-bones, for solid bones mean either a sluggish animal or a creature
of more or less aquatic habits, while hollow bones emphatically declare
a land animal, and an active one at that; and this, in the case of the
Dinosaurs, hints at predatory habits, the ability to catch and eat their
defenceless and more sluggish brethren. A claw, or, better yet, a
tooth, may confirm or refute this hint; for a blunt claw could not be
used in tearing prey limb from limb, nor would a double-edged tooth,
made for rending flesh, serve for champing grass.
But few bones of the feet, and especially the fore feet, are present,
these smaller parts of the skeleton having been washed away before the
ponderous frame was buried in the sand, and the best that can be done is
to follow the law of probabilities and put three toes on the hind foot
and five on the fore, two of these last without claws. The single blunt
round claw among our bones shows, as do the teeth, that Triceratops was
herbivorous; it also pointed a little downward, and this tells that in
the living animal the sole of the foot was a thick, soft pad, somewhat
as it is in the elephant and rhinoceros, and that the toes were not
entirely free from one another. There are less than a dozen vertebræ and
still fewer ribs, besides half a barrelful of pieces, from which to
reconstruct a backbone twenty feet long. That the ribs are part from one
side and part from another matters no more than it did in the case of
the leg-bones; but the backbone presents a more difficult problem,
since the pieces are not like so many checkers--all made after one
pattern--but each has an individuality of its own. The total number of
vertebræ must be guessed at (perhaps it would sound better to say
estimated, but it really means the same), and knowing that some sections
are from the front part of the vertebral column and some from the back,
we must fill in the gaps as best we may. The ribs offer a little aid in
this task, giving certain details of the vertebræ, while those in turn
tell something about the adjoining parts of the ribs. We finish our
Triceratops with a tail of moderate length, as indicated by the rapid
taper of the few vertebræ available, and from these we gather, too, that
in life the tail was round, and not flattened, and that it neither
served for swimming nor for a balancing pole. And so, little by little,
have been pieced together the fragments from which we have derived our
knowledge of the past, and thus has the palæontologist read the riddles
of the rocks.
[Illustration: Fig. 26.--Triceratops, He of the Three-horned Face. _From
a statuette by Charles R. Knight._]
To make these dry bones live again, to clothe them with flesh and
reconstruct the creature as he was or may have been in life, is, to
be honest, very largely guesswork, though to make a guess that shall
come anywhere near the mark not only demands a thorough knowledge of
anatomy--for the basis of all restoration must be the skeleton--but
calls for more than a passing acquaintance with the external appearance
of living animals. And while there is nothing in the bones to tell how
an animal is, or was, clad, they will at least show to what group the
creature belonged, and, that known, there are certain probabilities in
the case. A bird, for example, would certainly be clad in feathers.
Going a little farther, we might be pretty sure that the feathers of a
water-fowl would be thick and close; those of strictly terrestrial
birds, such as the ostrich and other flightless forms, lax and long.
These as general propositions; of course, in special cases, one might
easily come to grief, as in dealing with birds like penguins, which are
particularly adapted for an aquatic life, and have the feathers highly
modified. These birds depend upon their fat, and not on their feathers,
for warmth, and so their feathers have become a sort of cross between
scales and hairs. Hair and fur belong to mammals only, although these
creatures show much variety in their outer covering. The thoroughly
marine whales have discarded furs and adopted a smooth and slippery
skin,[9] well adapted to movement through the water, relying for warmth
on a thick undershirt of blubber. The earless seals that pass much of
their time on the ice have just enough hair to keep them from absolute
contact with it, warmth again being provided for by blubber. The fur
seals, which for several months in the year dwell largely on land, have
a coat of fur and hair, although warmth is mostly furnished, or rather
kept in, by fat.
[9] _The reader is warned that this is a mere figure of speech, for, of
course, the process of adaptation to surroundings is passive, not
active, although there is a most unfortunate tendency among writers on
evolution, and particularly on mimicry, to speak of it as active. The
writer believes that no animal in the first stages of mimicry,
consciously mimics or endeavors to resemble another animal or any part
of its surroundings, but a habit at first accidental may in time become
more or less conscious._
No reptile, therefore, would be covered with feathers, neither, judging
from those we know to-day, would they be clad in fur or hair; but, such
coverings being barred out, there remain a great variety of plates and
scales to choose from. Folds and frills, crests and dewlaps, like
beauty, are but skin deep, and, being thus superficial, ordinarily leave
no trace of their former presence, and in respect to them the
reconstructor must trust to his imagination, with the law of
probabilities as a check rein to his fancy. This law would tell us that
such ornaments must not be so placed as to be in the way, and that while
there would be a possibility--one might even say probability--of the
great, short-headed, iguana-like Dinosaurs having dewlaps, that there
would be no great likelihood of their possessing ruffs such as that of
the Australian Chlamydosaurus (mantled lizard) to flap about their ears.
Even Stegosaurus, with his bizarre array of great plates and spines,
kept them on his back, out of the way. Such festal ornamentation would,
however, more likely be found in small, active creatures, the larger
beasts contenting themselves with plates and folds.
Spines and plates usually leave some trace of their existence, for they
consist of a super-structure of skin or horn, built on a foundation of
bone; and while even horn decomposes too quickly to "petrify," the bone
will become fossilized and changed into enduring stone. But while this
affords a pretty sure guide to the general shape of the investing horn,
it does not give all the details, and there may have been ridges and
furrows and sculpturing that we know not of.
Knowing, then, what the probabilities are, we have some guide to the
character of the covering that should be placed on an animal, and if we
may not be sure as to what should be done, we may be pretty certain what
should not.
For example, to depict a Dinosaur with smooth, rubbery hide walking
about on dry land would be to violate the probabilities, for only such
exclusively aquatic creatures as the whales among mammals, and the
salamanders among batrachians, are clothed in smooth, shiny skin. There
might, however, be reason to suspect that a creature largely aquatic in
its habits did occasionally venture on land, as, for instance, when
vertebræ that seem illy adapted for carrying the weight of a land animal
are found in company with huge limb-bones and massive feet we may feel
reasonably certain that their owner passed at least a portion of his
time on _terra firma_.
So much for the probabilities as to the covering of animals known to us
only by their fossil remains; but it is often possible to go beyond
this, and to state certainly how they were clad. For while the chances
are small that any trace of the covering of an extinct animal, other
than bony plates, will be preserved, Nature does now and then seem to
have relented, and occasionally some animal settled to rest where it was
so quickly and quietly covered with fine mud that the impression of
small scales, feathers, or even smooth skin, was preserved; curiously
enough, there seems to be scarcely any record of the imprint of hair.
Then, too, it is to be remembered that while the chances were very much
against such preservation, in the thousands or millions of times
creatures died the millionth chance might come uppermost.
Silhouettes of those marine reptiles, the Ichthyosaurs, have been found,
probably made by the slow carbonization of animal matter, showing not
only the form of the body and tail, but revealing the existence of an
unsuspected back fin. And yet these animals were apparently clad in a
skin as thin and smooth as that of a whale. Impressions of feathers were
known long before the discovery of Archæopteryx; a few have been found
in the Green River and Florissant shales of Wyoming, and a Hesperornis
in the collection of the State University of Kansas shows traces of the
existence of long, soft feathers on the legs and very clear imprints of
the scales and reticulated skin that covered the tarsus. From the Chalk
of Kansas, too, came the example of Tylosaur, showing that the back of
this animal was decorated with the crest shown in Mr. Knight's
restoration, one not unlike that of the modern iguana. From the Laramie
sandstone of Montana Mr. Hatcher and Mr. Butler have obtained the
impressions of portions of the skin of the great Dinosaur, Thespesius,
which show that the covering of this animal consisted largely, if not
entirely, of small, irregularly hexagonal horny scutes, slightly
thickened in the centre. The quarries of lithographic stone at
Solenhofen have yielded a few specimens of flying reptiles,
pterodactyls, which not only verify the correctness of the inference
that these creatures possessed membranous wings, like the bats, but show
the exact shape, and it was sometimes very curious, of this membrane.
And each and all of these wonderfully preserved specimens serve both to
check and guide the restorer in his task of clothing the animal as it
was in life.
And all this help is needed, for it is an easy matter to make a
wide-sweeping deduction, apparently resting on a good basis of fact, and
yet erroneous. Remains of the Mammoth and Woolly Rhinoceros, found in
Siberia and Northern Europe, were thought to indicate that at the period
when these animals lived the climate was mild, a very natural inference,
since the elephants and rhinoceroses we now know are all inhabitants of
tropical climes. But the discovery of more or less complete specimens
makes it evident that the climate was not particularly mild; the
animals were simply adapted to it; instead of being naked like their
modern relatives, they were dressed for the climate in a woolly
covering. We think of the tiger as prowling through the jungles of
India, but he ranges so far north that in some localities this beast
preys upon reindeer, which are among the most northern of large mammals,
and there the tiger is clad in fairly thick fur.
When we come to coloring a reconstructed animal we have absolutely no
guide, unless we assume that the larger a creature the more soberly will
it be colored. The great land animals of to-day, the elephant and
rhinoceros, to say nothing of the aquatic hippopotamus, are very dully
colored, and while this sombre coloration is to-day a protection,
rendering these animals less easily seen by man than they otherwise
would be, yet at the time this color was developing man was not nor were
there enemies sufficiently formidable to menace the race of elephantine
creatures.
For where mere size furnishes sufficient protection one would hardly
expect to find protective coloration as well, unless indeed a creature
preyed upon others, when it might be advantageous to enable a predatory
animal to steal upon its prey.
Color often exists (or is supposed to) as a sexual characteristic, to
render the male of a species attractive to, or readily recognizable by,
the female, but in the case of large animals mere size is quite enough
to render them conspicuous, and possibly this may be one of the factors
in the dull coloration of large animals.
So while a green and yellow Triceratops would undoubtedly have been a
conspicuous feature in the Cretaceous landscape, from what we know of
existing animals it seems best to curb our fancy and, so far as large
Dinosaurs are concerned, employ the colors of a Rembrandt rather than
those of a sign painter.
Aids, or at least hints, to the coloration of extinct animals are to be
found in the coloration of the young of various living species, for as
the changes undergone by the embryo are in a measure an epitome of the
changes undergone by a species during its evolution, so the brief color
phases or markings of the young are considered to represent the
ordinary coloring of distant ancestors. Young thrushes are spotted,
young ostriches and grebes are irregularly striped, young lions are
spotted, and in restoring the early horse, or Hyracothere, Professor
Osborn had the animal represented as faintly striped, for the reason
that zebras, the wild horses of to-day, are striped, and because the
ass, which is a primitive type of horse, is striped over the shoulders,
these being hints that the earlier horse-like forms were also striped.
Thus just as the skeleton of a Dinosaur may be a composite structure,
made up of the bones of a dozen individuals, and these in turn mosaics
of many fragments, so may the semblance of the living animal be based on
a fact, pieced out with a probability and completed by a bit of theory.
_REFERENCES_
_There is a large series of restorations of extinct animals, prepared by
Mr. Charles R. Knight, under the direction of Professor Osborn, in the
Hall of Palæontology of the American Museum of Natural History, and
these are later to be reproduced and issued in portfolio form._
_Should the reader visit Princeton, he may see in the museum there a
number of B. Waterhouse Hawkins's creations--creations is the proper
word--which are of interest as examples of the early work in this line._
_The "Report of the Smithsonian Institution for 1900" contains an
article on "The Restoration of Extinct Animals," pages 479-492, which
includes a number of plates showing the progress that has been made in
this direction._
[Illustration: Fig. 27.--A Hint of Buried Treasures.]
VIII
FEATHERED GIANTS
_"There were giants in the earth in those days."_
Nearly every group of animals has its giants, its species which tower
above their fellows as Goliath of Gath stood head and shoulders above
the Philistine hosts; and while some of these are giants only in
comparison with their fellows, belonging to families whose members are
short of stature, others are sufficiently great to be called giants
under any circumstances. Some of these giants live to-day, some have but
recently passed away, and some ceased to be long ages before man trod
this earth. The most gigantic of mammals--the whales--still survive, and
the elephant of to-day suffers but little in comparison with the
mammoth of yesterday; the monstrous Dinosaurs, greatest of all
reptiles--greatest, in fact, of all animals that have walked the
earth--flourished thousands upon thousands of years ago. As for birds,
some of the giants among them are still living, some existed long
geologic periods ago, and a few have so recently vanished from the scene
that their memory still lingers amid the haze of tradition. The best
known among these, as well as the most recent in point of time, are the
Moas of New Zealand, first brought to notice by the Rev. W. Colenso,
later on Bishop of New Zealand, one of the many missionaries to whom
Science is under obligations. Early in 1838, Bishop Colenso, while on a
missionary visit to the East Cape region, heard from the natives of
Waiapu tales of a monstrous bird, called Moa, having the head of a man,
that inhabited the mountain-side some eighty miles away. This mighty
bird, the last of his race, was said to be attended by two equally huge
lizards that kept guard while he slept, and on the approach of man
wakened the Moa, who immediately rushed upon the intruders and trampled
them to death. None of the Maoris had seen this bird, but they had seen
and somewhat irreverently used for making parts of their fishing
tackle, bones of its extinct relatives, and these bones they declared to
be as large as those of an ox.
About the same time another missionary, the Rev. Richard Taylor, found a
bone ascribed to the Moa, and met with a very similar tradition among
the natives of a near-by district, only, as the foot of the rainbow
moves away as we move toward it, in his case the bird was said to dwell
in quite a different locality from that given by the natives of East
Cape. While, however, the Maoris were certain that the Moa still lived,
and to doubt its existence was little short of a crime, no one had
actually seen it, and as time went on and the bird still remained unseen
by any explorer, hope became doubt and doubt certainty, until it even
became a mooted question whether such a bird had existed within the past
ten centuries, to say nothing of having lived within the memory of man.
But if we do not know the living birds, their remains are scattered
broadcast over hillside and plain, concealed in caves, buried in the mud
of swamps, and from these we gain a good idea of their size and
structure, while chance has even made it possible to know something of
their color and general appearance. This chance was the discovery of a
few specimens, preserved in exceptionally dry caves on the South Island,
which not only had some of the bones still united by ligaments, but
patches of skin clinging to the bones, and bearing numerous feathers of
a chestnut color tipped with white. These small, straggling, rusty
feathers are not much to look at, but when we reflect that they have
been preserved for centuries without any care whatever, while the
buffalo bugs have devoured our best Smyrna rugs in spite of all possible
precautions, our respect for them increases.
[Illustration: Fig. 28.--Relics of the Moa.]
From the bones we learn that there were a great many kinds of Moas,
twenty at least, ranging in size from those little larger than a turkey
to that giant among giants, _Dinornis maximus_, which stood at least ten
feet high,[10] or two feet higher than the largest ostrich, and may
well claim the distinction of being the tallest of all known birds. We
also learn from the bones that not only were the Moas flightless, but
that many of them were absolutely wingless, being devoid even of such
vestiges of wings as we find in the Cassowary or Apteryx. But if Nature
deprived these birds of wings, she made ample amends in the matter of
legs, those of some species, the Elephant-footed Moa, _Pachyornis
elephantopus_, for example, being so massively built as to cause one to
wonder what the owner used them for, although the generally accepted
theory is that they were used for scratching up the roots of ferns on
which the Moas are believed to have fed. And if a blow from an irate
ostrich is sufficient to fell a man, what must have been the kicking
power of an able-bodied Moa? Beside this bird the ostrich would appear
as slim and graceful as a gazelle beside a prize ox.
[10] _The height of the Moas, and even of some species of Æpyornis, is
often stated to be twelve or fourteen feet, but such a height can only
be obtained by placing the skeleton in a wholly unnatural attitude._
The Moas were confined to New Zealand, some species inhabiting the North
Island, some the South, very few being common to both, and from these
peculiarities of distribution geologists deduce that at some early
period in the history of the earth the two islands formed one, that
later on the land subsided, leaving the islands separated by a strait,
and that since this subsidence there has been sufficient time for the
development of the species peculiar to each island. Although Moas were
still numerous when man made his appearance in this part of the world,
the large deposits of their bones indicate that they were on the wane,
and that natural causes had already reduced the feathered population of
these islands. A glacial period is believed to have wrought their
destruction, and in one great morass, abounding in springs, their bones
occur in such enormous numbers, layer upon layer, that it is thought the
birds sought the place where the flowing springs might afford their feet
at least some respite from the biting cold, and there perished miserably
by thousands.
What Nature spared man finished, and legends of Moa hunts and Moa feasts
still lingered among the Maoris when the white man came and began in
turn the extermination of the Maori. The theory has been advanced, with
much to support it, that the big birds were eaten off the face of the
earth by an earlier race than the Maoris, and that after the extirpation
of the Moas the craving for flesh naturally led to cannibalism. But by
whomsoever the destruction was wrought, the result was the same, the
habitat of these feathered giants knew them no longer, while multitudes
of charred bones, interspersed with fragments of egg-shells, bear
testimony to former barbaric feasts.
It is a far cry from New Zealand to Madagascar, but thither must we go,
for that island was, pity we cannot say is, inhabited by a race of giant
birds from whose eggs it has been thought may have been hatched the Roc
of Sindbad. Arabian tales, as we all know, locate the Roc either in
Madagascar or in some adjacent island to the north and east, and it is
far from unlikely that legends of the Æpyornis, backed by the
substantial proof of its enormous eggs, may have been the slight
foundation of fact whereon the story-teller erected his structure of
fiction. True, the Roc of fable was a gigantic bird of prey capable of
bearing away an elephant in its talons, while the Æpyornis has shed its
wings and shrunk to dimensions little larger than an ostrich, but this
is the inevitable result of closer acquaintance and the application of a
two-foot rule.
Like the Moa the Æpyornis seems to have lived in tradition long after it
became extinct, for a French history of Madagascar, published as early
as 1658 makes mention of a large bird, or kind of ostrich, said to
inhabit the southern end of the island. Still, in spite of bones having
been found that bear evident traces of the handiwork of man, it is
possible that this and other reports were due to the obvious necessity
of having some bird to account for the presence of the eggs.
The actual introduction of the Æpyornis to science took place in 1834,
when a French traveller sent Jules Verreaux, the ornithologist, a sketch
of a huge egg, saying that he had seen two of that size, one sawed in
twain to make bowls, the other, traversed by a stick, serving in the
preparation of rice uses somewhat in contrast with the proverbial
fragility of egg-shells. A little later another traveller procured some
fragments of egg-shells, but it was not until 1851 that any entire eggs
were obtained, when two were secured, and with a few bones sent to
France, where Geoffroy St. Hilaire bestowed upon them the name of
_Æpyornis maximus_ (the greatest lofty bird). Maximus the eggs remain,
for they still hold the record for size; but so far as the bird that is
supposed to have laid them is concerned, the name was a little
premature, for other and larger species subsequently came to hand.
Between the Æpyornithes and the Moas Science has had a hard time, for
the supply of big words was not large enough to go around, and some had
to do duty twice. In the way of generic names we have Dinornis, terrible
bird; Æpyornis, high bird; Pachyornis, stout bird; and Brontornis,
thunder bird, while for specific names there are robustus, maximus,
titan; gravis, heavy; immanis, enormous; crassus, stout; ingens, great;
and elephantopus, elephant-footed--truly a goodly array of
large-sounding words. But to return to the big eggs! Usually we look
upon those of the ostrich as pretty large, but an ostrich egg measures
4-1/2 by 6 inches, while that of the Æpyornis is 9 by 13 inches; or, to
put it another way, it would hold the contents of six ostrichs' eggs, or
one hundred and forty-eight hens' eggs, or thirty thousand humming
birds' eggs; and while this is very much smaller than a waterbutt, it is
still as large as a bucket, and one or two such eggs might suffice to
make an omelet for Gargantua himself.
The size of an egg is no safe criterion of the size of the bird that
laid it, for a large bird may lay a small egg, or a small bird a large
one. Comparing the egg of the great Moa with that of our Æpyornis one
might think the latter much the larger bird, say twelve feet in height,
when the facts in the case are that while there was no great difference
in the weight of the two, that difference, and a superiority of at least
two feet in height, are in favor of the bird that laid the smaller egg.
The record of large eggs, however, belongs to the Apteryx, a New Zealand
bird smaller than a hen, though distantly related to the Moas, which
lays an egg about one-third of its own weight, measuring 3 by 5 inches;
perhaps it is not to be wondered at that the bird lays but two.
Although most of the eggs of these big birds that have been found have
literally been unearthed from the muck of swamps, now and then one comes
to light in a more interesting manner as, for example, when a perfect
egg of Æpyornis was found afloat after a hurricane, bobbing serenely up
and down with the waves near St. Augustine's Bay, or when an egg of the
Moa was exhumed from an ancient Maori grave, where for years it had lain
unharmed, safely clasped between the skeleton fingers of the occupant.
So far very few of these huge eggs have made their way to this country,
and the only egg of Æpyornis now on this side of the water is the
property of a private individual.
Most recent in point of discovery, but oldest in point of time, are the
giant birds from Patagonia, which are burdened with the name of
Phororhacidæ, a name that originated in an error, although the error may
well be excused. The first fragment of one of these great birds to come
to light was a portion of the lower jaw, and this was so massive, so
un-bird-like, that the finder dubbed it _Phororhacos_, and so it must
remain.
[Illustration: Fig. 29.--Eggs of Feathered Giants, Æpyornis, Ostrich,
Moa, Compared with a Hen's Egg.]
It is a pity that all the large names were used up before this group of
birds was discovered, and it is particularly unfortunate that Dinornis,
terrible bird, was applied to the root-eating Moas, for these Patagonian
birds, with their massive limbs, huge heads and hooked beaks, were truly
worthy of such a name; and although in nowise related to the eagles,
they may in habit have been terrestrial birds of prey. Not all the
members of this family are giants, for as in other groups, some are big
and some little, but the largest among them might be styled the Daniel
Lambert of the feathered race. _Brontornis_, for example, the thunder
bird, or as the irreverent translate it, the thundering big bird, had
leg-bones larger than those of an ox, the drumstick measuring 30 inches
in length by 2-1/2 inches in diameter, or 4-1/4 inches across the ends,
while the tarsus, or lower bone of the leg to which the toes are
attached, was 16-1/2 inches long and 5-1/2 inches wide where the toes
join on. Bear this in mind the next time you see a large turkey, or
compare these bones with those of an ostrich: but lest you may forget,
it may be said that the same bone of a fourteen-pound turkey is 5-1/2
inches long, and one inch wide at either end, while that of an ostrich
measures 19 inches long and 2 inches across the toes, or 3 at the upper
end.
If Brontornis was a heavy-limbed bird, he was not without near rivals
among the Moas, while the great Phororhacos, one of his contemporaries,
was not only nearly as large, but quite unique in build. Imagine a bird
seven or eight feet in height from the sole of his big, sharp-clawed
feet, to the top of his huge head, poise this head on a neck as thick as
that of a horse, arm it with a beak as sharp as an icepick and almost as
formidable, and you have a fair idea of this feathered giant of the
ancient pampas. The head indeed was truly colossal for that of a bird,
measuring 23 inches in length by 7 in depth, while that of the racehorse
Lexington, and he was a good-sized horse, measures 22 inches long by
5-1/2 inches deep. The depth of the jaw is omitted because we wish to
make as good a case as possible for the bird, and the jaw of a horse is
so deep as to give him an undue advantage in that respect.
[Illustration: Fig. 30.--Skull of Phororhacos Compared with that of the
Race-horse Lexington.]
We can only speculate on the food of these great birds, and for aught we
know to the contrary they may have caught fish, fed upon carrion, or
used their powerful feet and huge beaks for grubbing roots; but if they
were not more or less carnivorous, preying upon such reptiles, mammals
and other birds as came within reach, then nature apparently made a
mistake in giving them such a formidable equipment of beak and claw. So
far as habits go we might be justified in calling them cursorial birds
of prey.
[Illustration: Fig. 31.--Leg of a Horse Compared with that of the Giant
Moa.]
We really know very little about these Patagonian giants, but they are
interesting not only from their great size and astounding skulls, but
because of the early age (Miocene) at which they lived and because in
spite of their bulk they are in nowise related to the ostriches, but
belong near the heron family. As usual, we have no idea why they became
extinct, but in this instance man is guiltless, for they lived and died
long before he made his appearance, and the ever-convenient hypothesis
"change of climate" may be responsible for their disappearance.
Something, perhaps, remains to be said concerning the causes which seem
to have led to the development of these giant birds, as well as the
reasons for their flightless condition and peculiar distribution, for it
will be noticed that, with the exception of the African and South
American ostriches the great flightless birds as a rule are, and were,
confined to uninhabited or sparsely populated islands, and this is
equally true of the many small, but equally flightless birds. It is a
seemingly harsh law of nature that all living beings shall live in a
more or less active struggle with each other and with their
surroundings, and that those creatures which possess some slight
advantage over their fellows in the matter of speed, or strength, or
ability to adapt themselves to surrounding conditions, shall prosper at
the expense of the others. In the power of flight, birds have a great
safeguard against changes of climate with their accompanying variations
in the supply of food, and, to a lesser extent, against their various
enemies, including man. This power of flight, acquired early in their
geological history, has enabled birds to spread over the length and
breadth of the globe as no other group of animals has done, and to
thrive under the most varying conditions, and it would seem that if this
power were lost it must sooner or later work harm. Now to-day we find no
great wingless birds in thickly populated regions, or where beasts of
prey abound; the ostriches roam the desert wastes of Arabia, Africa and
South America where men are few and savage beasts scarce, and against
these is placed a fleetness of foot inherited from ancestors who
acquired it before man was. The heavy cassowaries dwell in the thinly
inhabited, thickly wooded islands of Malaysia, where again there are no
large carnivores and where the dense vegetation is some safeguard
against man; the emu comes from the Australian plains, where also there
are no four-footed enemies[11] and where his ancestors dwelt in peace
before the advent of man. And the same things are true of the Moas, the
Æpyornithes, the flightless birds of Patagonia, the recent dodo of
Mauritius and the solitaire of Rodriguez, each and all of which
flourished in places where there were no men and practically no other
enemies. Hence we deduce that absence of enemies is the prime factor in
the existence of flightless birds,[12] although presence of food is an
essential, while isolation, or restriction to a limited area, plays an
important part by keeping together those birds, or that race of birds,
whose members show a tendency to disuse their wings. It will be seen
that such combinations of circumstances will most naturally be found on
islands whose geological history is such that they have had no
connection with adjacent continents, or such a very ancient connection
that they were not then peopled with beasts of prey, while subsequently
their distance from other countries has prevented them from receiving
such population by accident in recent times and has also retarded the
arrival of man.
[11] _The dingo, or native dog, is not forgotten, but, like man, it is a
comparatively recent animal._
[12] _Note that in Tasmania, which is very near Australia, both in space
and in the character of its animals, there are two carnivorous mammals,
the Tasmanian "Wolf" and the Tasmanian Devil, and no flightless birds._
Once established, flightlessness and size play into one another's hands;
the flightless bird has no limit placed on its size[13] while granted a
food supply and immunity from man; the larger the bird the less the
necessity for wings to escape from four-footed foes. So long as the
climate was favorable and man absent, the big, clumsy bird might thrive,
but upon the coming of man, or in the face of any unfavorable change of
climate, he would be at a serious disadvantage and hence whenever either
of these two factors has been brought to bear against them the feathered
giants have vanished.
[13] _While we do not know the limit of size to a flying creature, none
has as yet been found whose wings would spread over twenty feet from tip
to tip, and it is evident that wings larger than this would demand great
strength for their manipulation._
_REFERENCES_
_There is a fine collection of mounted skeletons of various species of
Moas in the Museum of Comparative Zoology at Cambridge, Mass., and
another in the American Museum of Natural History, New York. A few
_other skeletons and numerous bones are to be found in other
institutions, but the author is not aware of any egg being in this
country. Specimens of the Æpyornis are rare in this country, but Mr.
Robert Gilfort, of Orange, N.J., is the possessor of a very fine egg. A
number of eggs have been sold in London, the prices ranging from £200
down to £42, this last being much less than prices paid for eggs of the
great auk. But then, the great auk is somewhat of a fad, and there are
just enough eggs in existence to bring one into the market every little
while. Besides, the number of eggs of the great auk is a fixed quantity,
while no one knows how many more of Æpyornis remain to be discovered in
the swamps of Madagascar. No specimens of the gigantic Patagonian birds
are now in this country, but a fine example of one of the smaller forms,
Pelycornis, including the only breast-bone yet found, is in the Museum
of Princeton University._
_The largest known tibia of a Moa, the longest bird-bone known, is in
the collection of the Canterbury Museum, Christchurch, New Zealand; it
is 3 feet 3 inches long. This, however, is exceptional, the measurements
of the leg-bones of an ordinary Dinornis maximus being as follows:
Femur, 18 inches; tibia, 32 inches; tarsus, 19 inches, a total of 5 feet
9 inches. The egg measures 10-1/2 by 6-1/2 inches._
_There is plenty of literature, and very interesting literature,
about the Moas, but, unfortunately, the best of it is not always
accessible, being contained in the "New Zealand Journal of Science" and
the "Transactions of the New Zealand Institute." The volume of
"Transactions" for 1893, being vol. xxvi., contains a very full list of
articles relating to the Moas, compiled by Mr. A. Hamilton; it will be
found to commence on page 229. There is a good article on Moa in
Newton's "Dictionary of Birds," a book that should be in every library._
[Illustration: Fig. 32.--The Three Giants, Phororhacos, Moa, Ostrich.]
IX
THE ANCESTRY OF THE HORSE
"_Said the little Eohippus
I am going to be a horse
And on my middle finger-nails
To run my earthly course._"
The American whose ancestors came over in the "Mayflower" has a proper
pride in the length of the line of his descent. The Englishman whose
genealogical tree sprang up at the time of William the Conqueror has, in
its eight centuries of growth, still larger occasion for pluming himself
on the antiquity of his family. But the pedigree of even the latter is a
thing of yesterday when compared with that of the horse, whose family
records, according to Professor Osborn, reach backward for something
like 2,000,000 years. And if, as we have been told, "it is a good thing
to have ancestors, but sometimes a little hard on the ancestor," in
this instance at least the founders of the family have every reason to
regard their descendants with undisguised pride. For the horse family
started in life in a small way, and the first of the line, the
Hyracotherium, was "a little animal no bigger than a fox, and on
five[14] toes he scampered over Tertiary rocks," in the age called
Eocene, because it was the morning of life for the great group of
mammals whose culminating point was man. At that time, western North
America was a country of many lakes, for the most part comparatively
shallow, around the reedy margins of which moved a host of animals,
quite unlike those of to-day, and yet foreshadowing them, the
forerunners of the rhinoceros, tapir, and the horse.
[14] _Four, to be exact; but we prefer to sacrifice the foot of the
Hyracothere rather than to take liberties with one of the feet of Mrs.
Stetson's poem._
The early horse--we may call him so by courtesy, although he was then
very far from being a true horse--was an insignificant little creature,
apparently far less likely to succeed in life's race than his bulky
competitors, and yet, by making the most of their opportunities, his
descendants have survived, while most of theirs have dropped by the
wayside; and finally, by the aid of man, the horse has become spread
over the length and breadth of the habitable globe.
[Illustration: Fig. 33.--Skeleton of the Modern Horse and of His Eocene
Ancestor.]
Now right here it may be asked, How do we know that the little
Hyracothere _was_ the progenitor of the horse, and how can it be shown
that there is any bond of kinship between him and, for example, the
great French Percheron? There is only one way in which we can obtain
this knowledge, and but one method by which the relationship can be
shown, and that is by collecting the fossil remains of animals long
extinct and comparing them with the bones of the recent horse, a branch
of science known as Palæontology. It has taken a very long time to
gather the necessary evidence, and it has taken a vast amount of hard
work in our western Territories, for "the country that is as hot as
Hades, watered by stagnant alkali pools, is almost invariably the
richest in fossils." Likewise it has called for the expenditure of much
time and more patience to put together some of this petrified evidence,
fragmentary in every sense of the word, and get it into such shape that
it could be handled by the anatomist. Still, the work has been done,
and, link by link, the chain has been constructed that unites the horse
of to-day with the horse of very many yesterdays.
The very first links in this chain are the remains of the bronze age
and those found among the ruins of the ancient Swiss lake dwellings; but
earlier still than these are the bones of horses found abundantly in
northern Europe, Asia, and America. The individual bones and teeth of
some of these horses are scarcely distinguishable from those of to-day,
a fact noted in the name, _Equus fraternus_, applied to one species; and
when teeth alone are found, it is at times practically impossible to say
whether they belong to a fossil horse or to a modern animal. But when
enough scattered bones are gathered to make a fairly complete skeleton,
it becomes evident that the fossil horse had a proportionately larger
head and smaller feet than his existing relative, and that he was a
little more like an ass or zebra, for the latter, spite of his gay coat,
is a near relative of the lowly ass. Moreover, primitive man made
sketches of the primitive horse, just as he did of the mammoth, and
these indicate that the horse of those days was something like an
overgrown Shetland pony, low and heavily built, large-headed and
rough-coated. For the old cave-dwellers of Europe were intimately
acquainted with the prehistoric horses, using them for food, as they
did almost every animal that fell beneath their flint arrows and stone
axes. And if one may judge from the abundance of bones, the horses must
have roamed about in bands, just as the horses escaped from civilization
roam, or have roamed, over the pampas of South America and the prairies
of the West.
The horse was just as abundant in North America in Pleistocene time as
in Europe; but there is no evidence to show that it was contemporary
with early man in North America, and, even were this the case, it is
generally believed that long before the discovery of America the horse
had disappeared. And yet, so plentiful and so fresh are his remains, and
so much like those of the mustang, that the late Professor Cope was wont
to say that it almost seemed as if the horse _might_ have lingered in
Texas until the coming of the white man. And Sir William Flower wrote:
"There is a possibility of the animal having still existed, in a wild
state, in some parts of the continent remote from that which was first
visited by the Spaniards, where they were certainly unknown. It has
been suggested that the horses which were found by Cabot in La Plata in
1530 cannot have been introduced."
Still we have not the least little bit of positive proof that such was
the case, and although the site of many an ancient Indian village has
been carefully explored, no bones of the horse have come to light, or if
they have been found, bones of the ox or sheep were also present to tell
that the village was occupied long after the advent of the whites. It is
also a curious fact that within historic times there have been no wild
horses, in the true sense of the word, unless indeed those found on the
steppes north of the Sea of Azof be wild, and this is very doubtful. But
long before the dawn of history the horse was domesticated in Europe,
and Cæsar found the Germans, and even the old Britons, using war
chariots drawn by horses--for the first use man seems to have made of
the horse was to aid him in killing off his fellow-man, and not until
comparatively modern times was the animal employed in the peaceful arts
of agriculture. The immediate predecessors of these horses were
considerably smaller, being about the size and build of a pony, but
they were very much like a horse in structure, save that the teeth were
shorter. As they lived during Pliocene times, they have been named
"Pliohippus."
Going back into the past a step farther, though a pretty long step if we
reckon by years, we come upon a number of animals very much like horses,
save for certain cranial peculiarities and the fact that they had three
toes on each foot, while the horse, as every one knows, has but one toe.
Now, if we glance at the skeleton of a horse, we will see on either side
of the canon-bone, in the same situation as the upper part of the little
toes of the Hippotherium, as these three-toed horses are called, a long
slender bone, termed by veterinarians the splint bone; and it requires
no anatomical training to see that the bones in the two animals are the
same. The horse lacks the lower part of his side toes, that is all, just
as man will very probably some day lack the last bones of his little
toe. We find an approach to this condition in some of the Hippotheres
even, known as Protohippus, in which the side toes are quite small,
foreshadowing the time when they shall have disappeared entirely. It may
also be noted here that the splint bones of the horses of the bronze age
are a little longer than those of existing horses, and that they are
never united with the large central toe, while nowadays there is
something of a tendency for the three bones to fuse into one, although
part of this tendency the writer believes to be due to inflammation set
up by the strain of the pulling and hauling the animal is now called
upon to do. Some of these three-toed Hippotheres are not in the direct
line of ancestry of the horse, but are side branches on the family tree,
having become so highly specialized in certain directions that no
further progress horseward was possible.
Backward still, and the bones we find in the Miocene strata of the West,
belonging to those ancestors of the horse to which the name of
Mesohippus has been given because they are midway in time and structure
between the horse of the past and present, tell us that then all horses
were small and that all had three toes on a foot, while the fore feet
bore even the suggestion of a fourth toe. From this to our Eocene
Hyracothere with four toes is only another long-time step. We may go
even beyond this in time and structure, and carry back the line of the
horse to animals which only remotely resembled him and had five good
toes to a foot; but while these contained the possibility of a horse,
they made no show of it.
[Illustration: Fig. 34.--The Development of the Horse.]
Increase in size and decrease in number of the toes were not the only
changes that were required to transform the progeny of the Hyracothere
into a horse. These are the most evident; but the increased complexity
in the structure of the teeth was quite as important. The teeth of
gnawing animals have often been compared to a chisel which is made of a
steel plate with soft iron backing, and the teeth of a horse, or of
other grass-eating animals, are simply an elaboration of this idea. The
hard enamel, which represents the steel, is set in soft dentine, which
represents the iron, and in use the dentine wears away the faster of the
two, so that the enamel stands up in ridges, each tooth becoming, as it
is correctly termed, "a grinder." In a horse the plates of enamel form
curved, complex, irregular patterns; but as we go back in time, the
patterns become less and less elaborate, until in the Hyracothere,
standing at the foot of the family tree, the teeth are very simple in
structure. Moreover, his teeth were of limited growth, while those of
the horse grow for a considerable time, thus compensating for the wear
to which they are subjected.
We have, then, this direct evidence as to the genealogy of the horse,
that between the little Eocene Hyracothere and the modern horse we can
place a series of animals by which we can pass by gradual stages from
one to the other, and that as we come upward there is an increase in
stature, in the complexity of the teeth, and in the size of the brain.
At the same time, the number of toes decreases, which tells that the
animals were developing more and more speed; for it is a rule that the
fewer the toes the faster the animal: the fastest of birds, the ostrich,
has but two toes, and one of these is mostly ornamental; and the fastest
of mammals, the horse, has but one.
All breeders of fancy stock, particularly of pigeons and poultry,
recognize the tendency of animals to revert to the forms whence they
were derived and reproduce some character of a distant ancestor; to
"throw back," as the breeders term it. If now, instead of reproducing a
trait or feature possessed by some ancestor a score, a hundred, or
perhaps a thousand years ago, there should reappear a characteristic of
some ancestor that flourished 100,000 years back, we should have a
seeming abnormality, but really a case of reversion; and the more we
become acquainted with the structure of extinct animals and the
development of those now living, the better able are we to explain these
apparent abnormalities.
Bearing in mind that the two splint bones of the horse correspond to the
upper portions of the side toes of the Hippotherium and Mesohippus, it
is easy to see that if for any reason these should develop into toes,
they would make the foot of a modern horse appear like that of his
distant ancestor. While such a thing rarely happens, yet now and then
nature apparently does attempt to reproduce a horse's foot after the
ancient pattern, for occasionally we meet with a horse having, instead
of the single toe with which the average horse is satisfied, one or
possibly two extra toes. Sometimes the toe is extra in every sense of
the word, being a mere duplication of the central toe; but sometimes it
is an actual development of one of the splint bones. No less a personage
than Julius Cæsar possessed one of these polydactyl horses, and the
reporters of the _Daily Roman_ and the _Tiberian Gazette_ doubtless
wrote it up in good journalistic Latin, for we find the horse described
as having feet that were almost human, and as being looked upon with
great awe. While this is the most celebrated of extra-toed horses, other
and more plebeian individuals have been much more widely known through
having been exhibited throughout the country under such titles as
"Clique, the horse with six feet," "the eight-footed Cuban horse," and
so on; and possibly some of these are familiar to readers of this page.
So the collateral evidence, though scanty, bears out the circumstantial
proof, derived from fossil bones, that the horse has developed from a
many-toed ancestor; and the evidence points toward the little
Hyracothere as being that ancestor. It remains only to show some good
reason why this development should have taken place, or to indicate the
forces by which it was brought about. We have heard much about "the
survival of the fittest," a phrase which simply means that those animals
best adapted to their surroundings will survive, while those ill adapted
will perish. But it should be added that it means also that the animals
must be able to adapt themselves to changes in their environment, or to
change with it. Living beings cannot stand still indefinitely; they must
progress or perish. And this seems to have been the cause for the
extinction of the huge quadrupeds that flourished at the time of the
three-toed Miocene horse. They were adapted to their environment as it
was; but when the western mountains were thrust upward, cutting off the
moist winds from the Pacific, making great changes in the rainfall and
climate to the eastward of the Rocky Mountains, these big beasts, slow
of foot and dull of brain, could not keep pace with the change, and
their race vanished from the face of the earth. The day of the little
Hyracothere was at the beginning of the great series of changes by which
the lake country of the West, with its marshy flats and rank vegetation,
became transformed into dry uplands sparsely clad with fine grasses. On
these dry plains the more nimble-footed animals would have the advantage
in the struggle for existence; and while the four-toed foot would keep
its owner from sinking in soft ground, he was handicapped when it became
a question of speed, for not only is a fleet animal better able to flee
from danger than his slower fellows, but in time of drouth he can cover
the greater extent of territory in search of food or water. So, too, as
the rank rushes gave place to fine grasses, often browned and withered
beneath the summer's sun, the complex tooth had an advantage over that
of simpler structure, while the cutting-teeth, so completely developed
in the horse family, enabled their possessors to crop the grass as
closely as one could do it with scissors. Likewise, up to a certain
point, the largest, most powerful animal will not only conquer, or
escape from, his enemies, but prevail over rivals of his own kind as
well, and thus it came to pass that those early members of the horse
family who were preëminent in speed and stature, and harmonized best
with their surroundings, outstripped their fellows and transmitted these
qualities to their progeny, until, as a result of long ages of natural
selection, there was developed the modern horse. The rest man has done:
the heavy, slow-paced dray horse, the fleet trotter, the huge Percheron,
and the diminutive pony are one and all the recent products of
artificial selection.
_REFERENCES_
_The best collection of fossil horses, and one specially arranged to
illustrate the line of descent of the modern horse, is to be found in
the American Museum of Natural History, New York, but some good
specimens, of particular interest because they were described by
Professor Marsh and studied by Huxley are in the Yale University Museum.
They are referred to in Huxley's "American Addresses; Lectures on
Evolution." "The Horse," by Sir W. H. Flower, discusses the horse in a
popular manner from various points of view and contains numerous
references to books and articles on the subject from which anyone
wishing for further information could obtain it._
[Illustration: Fig. 35.--The Mammoth. _From a drawing by Charles R.
Knight._]
X
THE MAMMOTH
"_His legs were as thick as the bole of the beech,
His tusks as the buttonwood white,
While his lithe trunk wound like a sapling around
An oak in the whirlwind's might._"
_In the October number of McClure's Magazine for 1899 was
published a short story, "The Killing of the Mammoth," by "H.
Tukeman," which, to the amazement of the editors, was taken by
many readers not as fiction, but as a contribution to natural
history. Immediately after the appearance of that number of the
magazine, the authorities of the Smithsonian Institution, in
which the author had located the remains of the beast of his
fancy, were beset with visitors to see the stuffed mammoth, and
the daily mail of the Magazine, as well as that of the
Smithsonian Institution, was filled with inquiries for more
information and for requests to settle wagers as to whether it
was a true story or not. The contribution in question was
printed purely as fiction, with no idea of misleading the
public, and was entitled a story in the table of contents. We
doubt if any writer of realistic fiction ever had a more
general and convincing proof of success._
About three centuries ago, in 1696, a Russian, one Ludloff by name,
described some bones belonging to what the Tartars called "Mamantu";
later on, Blumenbach pressed the common name into scientific use as
"Mammut," and Cuvier gallicized this into "Mammouth," whence by an easy
transition we get our familiar mammoth. We are so accustomed to use the
word to describe anything of remarkable size that it would be only
natural to suppose that the name Mammoth was given to the extinct
elephant because of its extraordinary bulk. Exactly the reverse of this
is true, however, for the word came to have its present meaning because
the original possessor of the name was a huge animal. The Siberian
peasants called the creature "Mamantu," or "ground-dweller," because
they believed it to be a gigantic mole, passing its life beneath the
ground and perishing when by any accident it saw the light. The
reasoning that led to this belief was very simple and the logic very
good; no one had ever seen a live Mamantu, but there were plenty of its
bones lying at or near the surface; consequently if the animal did not
live above the ground, it must dwell below.
To-day, nearly every one knows that the mammoth was a sort of big,
hairy elephant, now extinct, and nearly every one has a general idea
that it lived in the North. There is some uncertainty as to whether the
mammoth was a mastodon, or the mastodon a mammoth, and there is a great
deal of misconception as to the size and abundance of this big beast. It
may be said in passing that the mastodon is only a second or third
cousin of the mammoth, but that the existing elephant of Asia is a very
near relative, certainly as near as a first cousin, possibly a very
great grandson. Popularly, the mammoth is supposed to have been a
colossus somewhere from twelve to twenty feet in height, beside whom
modern elephants would seem insignificant; but as "trout lose much in
dressing," so mammoths shrink in measuring, and while there were
doubtless Jumbos among them in the way of individuals of exceptional
magnitude, the majority were decidedly under Jumbo's size. The only
mounted mammoth skeleton in this country, that in the Chicago Academy of
Sciences, is one of the largest, the thigh-bone measuring five feet one
inch in length, or a foot more than that of Jumbo; and as Jumbo stood
eleven feet high, the rule of three applied to this thigh-bone would
give the living animal a height of thirteen feet eight inches. The
height of this specimen is given as thirteen feet in its bones, with an
estimate of fourteen feet in its clothes; but as the skeleton is
obviously mounted altogether too high, it is pretty safe to say that
thirteen feet is a good, fair allowance for the height of this animal
when alive. As for the majority of mammoths, they would not average more
than nine or ten feet high. Sir Samuel Baker tells us that he has seen
plenty of wild African elephants that would exceed Jumbo by a foot or
more, and while this must be accepted with caution, since unfortunately
he neglected to put a tape-line on them, yet Mr. Thomas Baines did
measure a specimen twelve feet high. This, coupled with Sir Samuel's
statement, indicates that there is not so much difference between the
mammoth and the elephant as there might be. This applies to the mammoth
_par excellence_, the species known scientifically as _Elephas
primigenius_, whose remains are found in many parts of the Northern
Hemisphere and occur abundantly in Siberia and Alaska. There were other
elephants than the mammoth, and some that exceeded him in size, notably
_Elephas meridionalis_ of southern Europe, and _Elephas columbi_ of our
Southern and Western States, but even the largest cannot positively be
asserted to have exceeded a height of thirteen feet. Tusks offer
convenient terms of comparison, and those of an average fully grown
mammoth are from eight to ten feet in length; those of the famous St.
Petersburg specimen and those of the huge specimen in Chicago measuring
respectively nine feet three inches, and nine feet eight inches. So far
as the writer is aware, the largest tusks actually measured are two from
Alaska, one twelve feet ten inches long, weighing 190 pounds, reported
by Mr. Jay Beach; and another eleven feet long, weighing 200 pounds,
noted by Mr. T. L. Brevig. Compared with these we have the big tusk that
used to stand on Fulton Street, New York, just an inch under nine feet
long, and weighing 184 pounds, or the largest shown at Chicago in 1893,
which was seven feet six inches long, and weighed 176 pounds. The
largest, most beautiful tusks, probably, ever seen in this country were
a pair brought from Zanzibar and displayed by Messrs. Tiffany & Company
in 1900. The measurements and weights of these were as follows: length
along outer curve, ten feet and three-fourths of an inch, circumference
one foot, eleven inches, weight, 224 pounds; length along outer curve,
ten feet, three and one-half inches, circumference two feet and
one-fourth of an inch, weight, 239 pounds.
For our knowledge of the external appearance of the mammoth we are
indebted to the more or less entire examples which have been found at
various times in Siberia, but mainly to the noted specimen found in 1799
near the Lena, embedded in the ice, where it had been reposing, so
geologists tell us, anywhere from 10,000 to 50,000 years. How the
creature gradually thawed out of its icy tomb, and the tusks were taken
by the discoverer and sold for ivory; how the dogs fed upon the flesh in
summer, while bears and wolves feasted upon it in winter; how the animal
was within an ace of being utterly lost to science when, at the last
moment, the mutilated remains were rescued by Mr. Adams, is an old
story, often told and retold. Suffice it to say that, besides the bones,
enough of the beast was preserved to tell us exactly what was the
covering of this ancient elephant, and to show that it was a creature
adapted to withstand the northern cold and fitted for living on the
branches of the birch and hemlock.
[Illustration: Fig. 36.--Skeleton of the Mammoth in the Royal Museum of
St. Petersburg.]
The exact birthplace of the mammoth is as uncertain as that of many
other great characters; but his earliest known resting-place is in the
Cromer Forest Beds of England, a country inhabited by him at a time when
the German Ocean was dry land and Great Britain part of a peninsula.
Here his remains are found to-day, while from the depths of the North
Sea the hardy trawlers have dredged hundreds, aye thousands, of mammoth
teeth in company with soles and turbot. If, then, the mammoth originated
in western Europe, and not in that great graveyard of fossil elephants,
northern India, eastward he went spreading over all Europe north of the
Pyrenees and Alps, save only Scandinavia, whose glaciers offered no
attractions, scattering his bones abundantly by the wayside to serve as
marvels for future ages. Strange indeed have been some of the tales to
which these and other elephantine remains have given rise when they came
to light in the good old days when knowledge of anatomy was small and
credulity was great. The least absurd theory concerning them was that
they were the bones of the elephants which Hannibal brought from Africa.
Occasionally they were brought forward as irrefutable evidences of the
deluge; but usually they figured as the bones of giants, the most famous
of them being known as Teutobochus, King of the Cimbri, a lusty warrior
said to have had a height of nineteen feet. Somewhat smaller, but still
of respectable height, fourteen feet, was "Littell Johne" of Scotland,
whereof Hector Boece wrote, concluding, in a moralizing tone, "Be quilk
(which) it appears how extravegant and squaire pepill grew in oure
regioun afore they were effeminat with lust and intemperance of mouth."
More than this, these bones have been venerated in Greece and Rome as
the remains of pagan heroes, and later on worshipped as relics of
Christian saints. Did not the church of Valencia possess an elephant
tooth which did duty as that of St. Christopher, and, so late as 1789,
was not a thigh-bone, figuring as the arm-bone of a saint, carried in
procession through the streets in order to bring rain?
Out of Europe eastward into Asia the mammoth took his way, and having
peopled that vast region, took advantage of a land connection then
existing between Asia and North America and walked over into Alaska, in
company with the forerunners of the bison and the ancestors of the
mountain sheep and Alaskan brown bear. Still eastward and southward he
went, until he came to the Atlantic coast, the latitude of southern New
York roughly marking the southern boundary of the broad domain over
which the mammoth roamed undisturbed.[15] Not that of necessity all this
vast area was occupied at one time; but this was the range of the
mammoth during Pleistocene time, for over all this region his bones and
teeth are found in greater or less abundance and in varying conditions
of preservation. In regions like parts of Siberia and Alaska, where the
bones are entombed in a wet and cold, often icy, soil, the bones and
tusks are almost as perfectly preserved as though they had been
deposited but a score of years ago, while remains so situated that they
have been subjected to varying conditions of dryness and moisture are
always in a fragmentary state. As previously noted, several more or less
entire carcasses of the mammoth have been discovered in Siberia, only to
be lost; and, while no entire animal has so far been found in Alaska,
some day one may yet come to light. That there is some possibility of
this is shown by the discovery, recorded by Mr. Dall, of the partial
skeleton of a mammoth in the bank of the Yukon with some of the fat
still present, and although this had been partially converted into
adipocere, it was fresh enough to be used by the natives for greasing,
not their boots, but their boats. And up to the present time this is the
nearest approach to finding a live mammoth in Alaska.
[15] _This must be taken as a very general statement, as the distinction
between and habitats of Elephas primigenius and Elephas columbi, the
southern mammoth, are not satisfactorily determined; moreover, the two
species overlap through a wide area of the West and Northwest._
As to why the mammoth became extinct, we _know_ absolutely nothing,
although various theories, some much more ingenious than plausible,
have been advanced to account for their extermination--they perished of
starvation; they were overtaken by floods on their supposed migrations
and drowned in detachments; they fell through the ice, equally in
detachments, and were swept out to sea. But all we can safely say is
that long ages ago the last one perished off the face of the earth.
Strange it is, too, that these mighty beasts, whose bulk was ample to
protect them against four-footed foes, and whose woolly coat was proof
against the cold, should have utterly vanished. They ranged from England
eastward to New York, almost around the world; from the Alps to the
Arctic Ocean; and in such numbers that to-day their tusks are articles
of commerce, and fossil ivory has its price current as well as wheat.
Mr. Boyd Dawkins thinks that the mammoth was actually exterminated by
early man, but, even granting that this might be true for southern and
western Europe, it could not be true of the herds that inhabited the
wastes of Siberia, or of the thousands that flourished in Alaska and the
western United States. So far as man is concerned, the mammoth might
still be living in these localities, where, before the discovery of gold
drew thousands of miners to Alaska, there were vast stretches of
wilderness wholly untrodden by the foot of man. Neither could this
theory account for the disappearance of the mastodon from North America,
where that animal covered so vast a stretch of territory that man,
unaided by nature, could have made little impression on its numbers.
That many were swept out to sea by the flooded rivers of Siberia is
certain, for some of the low islands off the coast are said to be formed
of sand, ice, and bones of the mammoth, and thence, for hundreds of
years, have come the tusks which are sold in the market beside those of
the African and Indian elephants.
That man was contemporary with the mammoth in southern Europe is fairly
certain, for not only are the remains of the mammoth and man's flint
weapons found together, but in a few instances some primeval Landseer
graved on slate, ivory, or reindeer antler a sketchy outline of the
beast, somewhat impressionistic perhaps, but still, like the work of a
true artist, preserving the salient features. We see the curved tusks,
the snaky trunk, and the shaggy coat that we know belonged to the
mammoth, and we may feel assured that if early man did not conquer the
clumsy creature with fire and flint, he yet gazed upon him from the safe
vantage point of some lofty tree or inaccessible rock, and then went
home to tell his wife and neighbors how the animal escaped because his
bow missed fire. That man and mammoth lived together in North America is
uncertain; so far there is no evidence to show that they did, although
the absence of such evidence is no proof that they did not. That any
live mammoth has for centuries been seen on the Alaskan tundras is
utterly improbable, and on Mr. C. H. Townsend seems to rest the
responsibility of having, though quite unintentionally, introduced the
Alaskan Live Mammoth into the columns of the daily press. It befell in
this wise: Among the varied duties of our revenue marine is that of
patrolling and exploring the shores of arctic Alaska and the waters of
the adjoining sea, and it is not so many years ago that the cutter
_Corwin_, if memory serves aright, held the record of farthest north on
the Pacific side. On one of these northern trips, to the Kotzebue Sound
region, famous for the abundance of its deposits of mammoth bones,[16]
the _Corwin_ carried Mr. Townsend, then naturalist to the United States
Fish Commission. At Cape Prince of Wales some natives came on board
bringing a few bones and tusks of the mammoth, and upon being questioned
as to whether or not any of the animals to which they pertained were
living, promptly replied that all were dead, inquiring in turn if the
white men had ever seen any, and if they knew how these animals, so
vastly larger than a reindeer, looked.
[16] _Elephant Point, at the mouth of the Buckland River, is so named
from the numbers of mammoth bones which have accumulated there._
Fortunately, or unfortunately, there was on board a text-book of geology
containing the well-known cut of the St. Petersburg mammoth, and this
was brought forth, greatly to the edification of the natives, who were
delighted at recognizing the curved tusks and the bones they knew so
well. Next the natives wished to know what the outside of the creature
looked like, and as Mr. Townsend had been at Ward's establishment in
Rochester when the first copy of the Stuttgart restoration was made, he
rose to the emergency, and made a sketch. This was taken ashore,
together with a copy of the cut of the skeleton that was laboriously
made by an Innuit sprawled out at full length on the deck. Now the
Innuits, as Mr. Townsend tells us, are great gadabouts, making long
sledge journeys in winter and equally long trips by boat in summer,
while each season they hold a regular fair on Kotzebue Sound, where a
thousand or two natives gather to barter and gossip. On these journeys
and at these gatherings the sketches were no doubt passed about, copied,
and recopied, until a large number of Innuits had become well acquainted
with the appearance of the mammoth, a knowledge that naturally they were
well pleased to display to any white visitors. Also, like the Celt, the
Alaskan native delights to give a "soft answer," and is always ready to
furnish the kind of information desired. Thus in due time the newspaper
man learned that the Alaskans could make pictures of the mammoth, and
that they had some knowledge of its size and habits; so with inference
and logic quite as good as that of the Tungusian peasant, the reporter
came to the conclusion that somewhere in the frozen wilderness the last
survivor of the mammoths must still be at large. And so, starting on the
Pacific coast, the Live Mammoth story wandered from paper to paper,
until it had spread throughout the length and breadth of the United
States, when it was captured by Mr. Tukeman, who with much artistic
color and some realistic touches, transferred it to _McClure's
Magazine_, and--unfortunately for the officials thereof--to the
Smithsonian Institution.
And now, once for all, it may be said that _there is no mounted mammoth_
to awe the visitor to the national collections or to any other; and yet
there seems no good and conclusive reason why there should not be. True,
there are no live mammoths to be had at any price; neither are their
carcasses to be had on demand; still there is good reason to believe
that a much smaller sum than that said to have been paid by Mr. Conradi
for the mammoth which is _not_ in the Smithsonian Institution, would
place one there.[17] It probably could not be done in one year; it might
not be possible in five years; but should any man of means wish to
secure enduring fame by showing the world the mammoth as it stood in
life, a hundred centuries ago, before the dawn of even tradition, he
could probably accomplish the result by the expenditure of a far less
sum than it would cost to participate in an international yacht race.
[17] _Since these lines were written another fine example of the Mammoth
has been discovered in Siberia and even now (Oct., 1901) an expedition
is on its way to secure the skin and skeleton for the Academy of Natural
Sciences at St. Petersburg._
_REFERENCES_
_The mounted skeleton of the mammoth in the museum of the Chicago
Academy of Science is still the only one on exhibition in the United
States; this specimen is probably the Southern Mammoth, Elephas columbi,
a species, or race, characterized by its great size and the coarse
structure of the teeth. Remains of the mammoth are common enough but,
save in Alaska, they are usually in a poor state of preservation or
consist of isolated bones or teeth. A great many skeletons of mammoth
have been found by gold miners in Alaska, and with proper care some of
these could undoubtedly have been secured. Naturally, however, the
miners do not feel like taking the time and trouble to exhume bones
whose value is uncertain, while the cost of transportation precludes the
bringing out of many specimens._
_Some reports of mammoths have been based on the bones of whales,
including a skull that was figured in the daily papers._
_Almost every museum has on exhibition teeth of the mammoth, and there
is a skull, though from a small individual, of the Southern Mammoth in
the American Museum of Natural History, New York._
_The tusk obtained by Mr. Beach and mentioned in the text still holds
the record for mammoth tusks. The greatest development of tusks
occurred in Elephas ganesa, a species found in Pliocene deposits of the
Siwalik Hills, India. This species appears not to have exceeded the
existing elephant in bulk, but the tusks are twelve feet nine inches
long, and two feet two inches in circumference. How the animal ever
carried them is a mystery, both on account of their size and their
enormous leverage. As for teeth, an upper grinder of Elephas columbi in
the United States National Museum is ten and one-half inches high, nine
inches wide, the grinding face being eight by five inches. This tooth,
which is unusually perfect, retaining the outer covering of cement, came
from Afton, Indian Territory, and weighs a little over fifteen pounds.
The lower tooth, shown in Fig. 38, is twelve inches long, and the
grinding face is nine by three and one-half inches; this is also from
Elephas columbi. Grinders of the Northern Mammoth are smaller, and the
plates of enamel thinner, and closer to one another. Mr. F. E. Andrews,
of Gunsight, Texas, reports having found a femur, or thigh-bone five
feet four inches long, and a humerus measuring four feet three inches,
these being the largest bones on record indicating an animal fourteen
feet high._
_There is a vast amount of literature relating to the mammoth, some of
it very untrustworthy. A list of all discoveries of specimens in the
flesh is given by Nordenskiold in "The Voyage of the Vega" and "The
Mammoth and the Flood" by Sir Henry Howorth, is a mine of information.
Mr. Townsend's "Alaska Live-Mammoth Story" may be found in "Forest and
Stream" for August 14, 1897._
[Illustration: Fig. 37.--The Mammoth as Engraved by a Primitive Artist
on a Piece of Mammoth Tusk.]
XI
THE MASTODON
"_... who shall place
A limit to the giant's unchained strength?_"
The name mastodon is given to a number of species of fossil elephants
differing from the true elephants, of which the mammoth is an example,
in the structure of the teeth. In the mastodons the crown, or grinding
face of the tooth, is formed by more or less regular /\-shaped cross
ridges, covered with enamel, while in the elephants the enamel takes the
form of narrow, pocket-shaped plates, set upright in the body of the
tooth. Moreover, in the mastodons the roots of the teeth are long
prongs, while in the elephants the roots are small and irregular. A
glance at the cuts will show these distinctions better than they can be
explained by words. Back in the past, however, we meet, as we should if
there is any truth in the theory of evolution, with elephants having an
intermediate pattern of teeth.
[Illustration: Fig. 38.--Tooth of Mastodon and of Mammoth.]
There is usually, or at least often, another point of difference between
elephants and mastodons, for many of the latter not only had tusks in
the upper, but in the lower jaw, and these are never found in any of the
true elephants. The lower tusks are longer and larger in the earlier
species of mastodon than in those of more recent age and in the latest
species, the common American mastodon, the little lower tusks were
usually shed early in life. These afford some hints of the relationships
of the mastodon; for in Europe are found remains of a huge beast well
called Dinotherium, or terrible animal, which possessed lower tusks
only, and these, instead of sticking out from the jaw are bent directly
downwards. No perfect skull of this creature has yet been found, but it
is believed to have had a short trunk. For a long time nothing but the
skull was known, and some naturalists thought the animal to have been a
gigantic manatee, or sea cow, and that the tusks were used for tearing
food from the bottom of rivers and for anchoring the animal to the bank,
just as the walrus uses his tusks for digging clams and climbing out
upon the ice. In the first restorations of Dinotherium it is represented
lying amidst reeds, the feet concealed from view, the head alone
visible, but now it is pictured as standing erect, for the discovery of
massive leg-bones has definitely settled the question as to whether it
did or did not have limbs.
There is another hint of relationship in the upper tusks of the earlier
mastodons, and this is the presence of a band of enamel running down
each tusk. In all gnawing animals the front, cutting teeth are formed of
soft dentine, or ivory, faced with a plate of enamel, just as the blade
of a chisel or plane is formed of a plate of tempered steel backed with
soft iron; the object of this being the same in both tooth and chisel,
to keep the edge sharp by wearing away the softer material. In the case
of the chisel this is done by a man with a grindstone, but with the
tooth it is performed automatically and more pleasantly by the gnawing
of food. In the mastodon and elephant the tusks, which are the
representatives of the cutting teeth of rodents, are wide apart, and of
course do not gnaw anything, but the presence of these enamel bands
hints at a time when they and their owner were smaller and differently
shaped, and the teeth were used for cutting. Thus, great though the
disparity of size may be, there is a suggestion that through the
mastodon the elephant is distantly related to the mouse, and that, could
we trace their respective pedigrees far enough, we might find a common
ancestor.
This presence of structures that are apparently of no use, often worse
than useless, is regarded as the survival of characters that once served
some good purpose, like the familiar buttons on the sleeve or at the
back of a man's coat, or the bows and ruffles on a woman's dress. We
are told that these are put on "to make the dress look pretty," but the
student regards the bows as vestiges of the time when there were no
buttons and hooks and eyes had not been invented, and dresses were tied
together with strings or ribbons. As for ruffles, they took the place of
flounces, and flounces are vestiges of the time when a young woman wore
the greater part of her wardrobe on her back, putting on one dress above
another, the bottoms of the skirts showing like so many flounces. So
buttons, ruffles, and the vermiform appendix of which we hear so much
all fall in the category of vestigial structures.
Where the mastodons originated, we know not: Señor Ameghino thinks their
ancestors are to be found in Patagonia, and he is very probably wrong;
Professor Cope thought they came from Asia, and he is probably right; or
they may have immigrated from the convenient Antarctica, which is called
up to account for various facts in the distribution of animals.[18]
[18] _During the past year, 1901, Mr. C. W. Andrews of the British
Museum has discovered in Egypt a small and primitive species of
mastodon, also the remains of another animal which he thinks may be the
long sought ancestor of the elephant family, which includes the mammoth
and mastodon._
Neither do we at present know just how many species of mastodons there
may have been in the Western Hemisphere, for most of them are known from
scattered teeth, single jaws, and odd bones, so that we cannot tell just
what differences may be due to sex or individual variation. It is
certain, however, that several distinct kinds, or species, have
inhabited various parts of North America, while remains of others occur
in South America. _The_ mastodon, however, the one most recent in point
of time, and the best known because its remains are scattered far and
wide over pretty much the length and breadth of the United States, and
are found also in southern and western Canada, is the well-named
_Mastodon americanus_,[19] and unless otherwise specified this alone
will be meant when the name mastodon is used. In some localities the
mastodon seems to have abounded, but between the Hudson and Connecticut
Rivers indications of its former presence are rare, and east of that
they are practically wanting. The best preserved specimens come from
Ulster and Orange Counties, New York, for these seem to have furnished
the animal with the best facilities for getting mired. Just west of the
Catskills, parallel with the valley of the Hudson, is a series of
meadows, bogs, and pools marking the sites of swamps that came into
existence after the recession of the mighty ice-sheet that long covered
eastern North America, and in these many a mastodon, seeking for food or
water, or merely wallowing in the mud, stuck fast and perished
miserably. And here to-day the spade of the farmer as he sinks a ditch
to drain what is left of some beaver pond of bygone days, strikes some
bone as brown and rugged as a root, so like a piece of water-soaked wood
that nine times out of ten it is taken for a fragment of tree-trunk.
[19] _This has also been called giganteus and ohioticus, but the name
americanus claims priority, and should therefore be used._
The first notice of the mastodon in North America goes back to 1712, and
is found in a letter from Cotton Mather to Dr. Woodward (of England?)
written at Boston on November 17th, in which he speaks of a large work
in manuscript entitled _Biblia Americana_, and gives as a sample a note
on the passage in Genesis (VI. 4) in which we read that "there were
giants in the earth in those days." We are told that this is confirmed
by "the bones and teeth of some large animal found lately in Albany, in
New England, which for some reason he thinks to be human; particularly a
tooth brought from the place where it was found to New York in 1705,
being a very large grinder, weighing four pounds and three quarters;
with a bone supposed to be a thigh-bone, seventeen feet long," the total
length of the body being taken as seventy-five feet. Thus bones of the
mastodon, as well as those of the mammoth, have done duty as those of
giants.
And as the first mastodon remains recorded from North America came from
the region west of the Hudson, so the first fairly complete skeleton
also came from that locality, secured at a very considerable outlay of
money and a still more considerable expenditure of labor by the
exertions of C. W. Peale. This specimen was described at some length by
Rembrandt Peale in a privately printed pamphlet, now unfortunately
rare, and described in some respects better than has been done by any
subsequent writer, since the points of difference between various parts
of the mastodon and elephant were clearly pointed out. This skeleton was
exhibited in London, and afterwards at Peale's Museum in Philadelphia
where, with much other valuable material, it was destroyed by fire.
Struck by the evident crushing power of the great ridged molars, Peale
was led to believe that the mastodon was a creature of carnivorous
habits, and so described it, but this error is excusable, the more that
to this day, when the mastodon is well known, and its description
published time and again in the daily papers, finders of the teeth often
consider them as belonging to some huge beast of prey.
Since the time of Peale several fine specimens have been taken from
Ulster and Orange Counties, among them the well-known "Warren Mastodon,"
and there is not the slightest doubt that many more will be recovered
from the meadows, swamps, and pond holes of these two counties.
[Illustration: Fig. 39.--The Missourium of Koch, from a Tracing of the
Figure Illustrating Koch's Description.]
The next mastodon to appear on the scene was the so-called Missourium of
Albert Koch, which he constructed somewhat as he did the Hydrarchus (see
p. 61) of several individuals pieced together, thus forming a skeleton
that was a monster in more ways than one. To heighten the effect, the
curved tusks were so placed that they stood out at right angles to the
sides of the head, like the swords upon the axles of ancient war
chariots. Like Peale's specimen this was exhibited in London, and there
it still remains, for, stripped of its superfluous bones, and remounted,
it may now be seen in the British Museum.
Many a mastodon has come to light since the time of Koch, for while it
is commonly supposed that remains of the animal are great rarities, as a
matter of fact they are quite common, and it may safely be said that
during the seasons of ditching, draining, and well-digging not a week
passes without one or more mastodons being unearthed. Not that these are
complete skeletons, very far from it, the majority of finds are
scattered teeth, crumbling tusks, or massive leg-bones, but still the
mastodon is far commoner in the museums of this country than is the
African elephant, for at the present date there are eleven of the former
to one of the latter, the single skeleton of African elephant being that
of Jumbo in the American Museum of Natural History. If one may judge by
the abundance of bones, mastodons must have been very numerous in some
favored localities such as parts of Michigan, Florida, and Missouri and
about Big Bone Lick, Ky. Perhaps the most noteworthy of all deposits is
that at Kimmswick, about twenty miles south of St. Louis, where in a
limited area Mr. L. W. Beehler has exhumed bones representing several
hundred individuals, varying in size from a mere baby mastodon up to the
great tusker whose wornout teeth proclaim that he had reached the limit
of even mastodonic old age. The spot where this remarkable deposit was
found is at the foot of a bluff near the junction of two little streams,
and it seems probable that in the days when these were larger the spring
floods swept down the bodies of animals that had perished during the
winter to ground in an eddy beneath the bluff. Or as the place abounds
in springs of sulphur and salt water it may be that this was where the
animals assembled during cold weather, just as the moas are believed to
have gathered in the swamps of New Zealand, and here the weaker died and
left their bones.
The mastodon must have looked very much like any other elephant, though
a little shorter in the legs and somewhat more heavily built than either
of the living species, while the head was a trifle flatter and the jaw
decidedly longer. The tusks are a variable quantity, sometimes merely
bowing outwards, often curving upwards to form a half circle; they were
never so long as the largest mammoth tusks, but to make up for this they
were a shade stouter for their length. As the mastodon ranged well to
the north it is fair to suppose that he may have been covered with long
hair, a supposition that seems to be borne out by the discovery, noted
by Rembrandt Peale, of a mass of long, coarse, woolly hair buried in one
of the swamps of Ulster County, New York. And with these facts in mind,
aided by photographs of various skeletons of mastodons, Mr. Gleeson
made the restoration which accompanies this chapter.
[Illustration: Fig. 40.--The Mastodon. _From a drawing by J. M.
Gleeson._]
As for the size of the mastodon, this, like that of the mammoth, is
popularly much over-estimated, and it is more than doubtful if any
attained the height of a full-grown African elephant. The largest femur,
or thigh-bone, that has come under the writer's notice was one he
measured as it lay in the earth at Kimmswick, and this was just four
feet long, three inches shorter than the thigh-bone of Jumbo. Several of
the largest thigh-bones measured show so striking an unanimity in size,
between 46 and 47 inches in length, that we may be pretty sure they
represent the average old "bull" mastodon, and if we say that these
animals stood ten feet high we are probably doing them full justice. An
occasional tusk reaches a length of ten feet, but seven or eight is the
usual size, with a diameter of as many inches, and this is no larger
than the tusks of the African elephant would grow if they had a chance.
It is painful to be obliged to scale down the mastodon as we have just
done the mammoth, but if any reader knows of specimens larger than those
noted, he should by all means publish their measurements.[20]
[20] _As skeletons are sometimes mounted, they stand a full foot or more
higher at the shoulders than the animal stood in life, this being caused
by raising the body until the shoulder-blades are far below the tips of
the vertebræ, a position they never assume in life._
The disappearance of the mastodon is as difficult to account for as that
of the mammoth, and, as will be noted, there is absolutely no evidence
to show that man had any hand in it. Neither can it be ascribed to
change of climate, for the mastodon, as indicated by the wide
distribution of its bones, was apparently adapted to a great diversity
of climates, and was as much at home amid the cool swamps of Michigan
and New York as on the warm savannas of Florida and Louisiana. Certainly
the much used, and abused, glacial epoch cannot be held accountable for
the extermination of the creature, for the mastodon came into New York
after the recession of the great ice-sheet, and tarried to so late a
date that bones buried in the swamps retain much of their animal
matter. So recent, comparatively speaking, has been the disappearance of
the mastodon, and so fresh-looking are some of its bones, that Thomas
Jefferson thought in his day that it might still be living in some part
of the then unexplored Northwest.
It is a moot question whether or not man and the mastodon were
contemporaries in North America, and while many there be who, like the
writer of these lines, believe that this was the case, an expression of
belief is not a demonstration of fact. The best that can be said is that
there are scattered bits of testimony, slight though they are, which
seem to point that way, but no one so strong by itself that it could not
be shaken by sharp cross-questioning and enable man to prove an alibi in
a trial by jury. For example, in the great bone deposit at Kimmswick,
Mo., Mr. Beehler found a flint arrowhead, but this may have lain just
over the bone-bearing layer, or have got in by some accident in
excavating. How easily a mistake may be made is shown by the report sent
to the United States National Museum of many arrowheads associated with
mastodon bones in a spring at Afton, Indian Territory. This spring was
investigated, and a few mastodon bones and flint arrowheads were found,
but the latter were in a stratum just above the bones, although this was
overlooked by the first diggers.[21] Koch reported finding charcoal and
arrowheads so associated with mastodon bones that he inferred the animal
to have been destroyed by fire and arrows after it became mired. It has
been said that Koch could have had no object in disseminating this
report, and hence that it may be credited, but he had just as much
interest in doing this as he did in fabricating the Hydrarchus and the
Missourium, and his testimony is not to be considered seriously. It
seems to be with the mastodon much as it is with the sea-serpent; the
latter never appears to a naturalist, remains of the former are never
found by a trained observer associated with indications of the presence
of man. Perhaps an exception should be made in the case of Professor J.
M. Clarke, who found fragments of charcoal in a deposit of muck under
some bones of mastodon.
[21] _This locality has just been carefully investigated by Mr. W. H.
Holmes of the United States National Museum who found bones of the
mastodon and Southern Mammoth associated with arrowheads. But he also
found fresh bones of bison, horse, and wolf, showing that these and the
arrowheads had simply sunk to the level of the older deposit._
We may pass by the so-called "Elephant Mound," which to the eye of an
unimaginative observer looks as if it might have been intended for any
one of several beasts; also, with bated breath and due respect for the
bitter controversy waged over them, pass we by the elephant pipes. There
remains, then, not a bit of man's handiwork, not a piece of pottery,
engraved stone, or scratched bone that can _unhesitatingly_ be said to
have been wrought into the shape of an elephant before the coming of the
white man. True, there is "The Lenape Stone," found near Doyleston, Pa.,
in 1872, a gorget graven on one side with the representation of men
attacking an elephant, while the other bears a number of figures of
various animals. The good faith of the finder of this stone is
unimpeachable, but it is a curious fact that, while this gorget is
elaborately decorated on both sides, no similar stone, out of all that
have been found, bears any image whatsoever. On the other hand, if not
made by the aborigines, who made it, why was it made, and why did nine
years elapse between the discovery of the first and second portions of
the broken ornament? These are questions the reader may decide for
himself; the author will only say that to his mind the drawing is too
elaborate, and depicts entirely too much to have been made by a
primitive artist. A much better bit of testimony seems to be presented
by a fragment of Fulgur shell found near Hollyoak, Del., and now in the
United States National Museum, which bears a very rudely scratched image
of an animal that may have been intended for a mastodon or a bison. This
piece of shell is undeniably old, but there is, unfortunately, the
uncertainty just mentioned as to the animal depicted. The familiar
legend of the Big Buffalo that destroyed animals and men and defied even
the lightnings of the Great Spirit has been thought by some to have
originated in a tradition of the mastodon handed down from ancient
times; but why consider that the mastodon is meant? Why not a legendary
bison that has increased with years of story-telling? And so the
co-existence of man and mastodon must rest as a case of not proven,
although there is a strong probability that the two did live together in
the dim ages of the past, and some day the evidence may come to light
that will prove it beyond a peradventure. If scientific men are charged
with obstinacy and unwarranted incredulity in declining to accept the
testimony so far presented, it must be remembered that the evidence as
to the existence of the sea serpent is far stronger, since it rests on
the testimony of eye-witnesses, and yet the creature himself has never
been seen by a trained observer, nor has any specimen, not a scale, a
tooth, or a bone, ever made its way into any museum.
_REFERENCES_
_There are at least eleven mounted skeletons of the Mastodon in the
United States, and the writer trusts he may be pardoned for mentioning
only those which are most accessible. These are in the American Museum
of Natural History, New York; the State Museum, Albany, N. Y.; Field
Columbian Museum, Chicago; Carnegie Museum, Pittsburg; Museum of
Comparative Zoölogy, Cambridge, Mass. There is no mounted skeleton in
the United States National Museum, nor has there ever been._
_The heaviest pair of tusks is in the possession of T. O. Tuttle,
Seneca, Mich., and they are nine and one-half inches in diameter, and a
little over eight feet long; very few tusks, however, reach eight inches
in diameter. The thigh-bone of an old male mastodon measures from
forty-five to forty-six and one-half inches long, the humerus from
thirty-five to forty inches. The height of the mounted skeleton is of
little value as an indication of size, since it depends so much upon the
manner in which the skeleton is mounted. The grinders of the mastodon
have three cross ridges, save the last, which has four, and a final
elevation, or heel. This does not apply to the teeth of very young
animals. The presence or absence of the last grinder will show whether
or not the animal is of full age and size, while the amount of wear
indicates the comparative age of the specimen._
_The skeleton of the "Warren Mastodon" is described at length by Dr. J.
C. Warren, in a quarto volume entitled "Mastodon Giganteus." There is
much information in a little book by J. P. MacLean, "Mastodon, Mammoth,
and Man," but the reader must not accept all its statements
unhesitatingly. The first volume, 1887, of the New Scribner's Magazine
contains an article on "American Elephant Myths," by Professor W. B.
Scott, but he is under an erroneous impression regarding the size of the
mastodon, and photographs of the Maya carvings show that their
resemblance to elephants has been exaggerated in the wood cuts. The
story of the Lenape Stone is told at length by H. C. Mercer in "The
Lenape Stone, or the Indian and the Mammoth."_
[Illustration: Fig. 41.--The Lenape Stone, Reduced.]
XII
WHY DO ANIMALS BECOME EXTINCT?
"_And Sultan after Sultan with his Pomp
Abode his destined Hour and went his way._"
It is often asked "why do animals become extinct?" but the question is
one to which it is impossible to give a comprehensive and satisfactory
reply; this chapter does not pretend to do so, merely to present a few
aspects of this complicated, many-sided problem.
In very many cases it may be said that actual extermination has not
taken place, but that in the course of evolution one species has passed
into another; species may have been lost, but the race, or phylum
endures, just as in the growth of a tree, the twigs and branches of the
sapling disappear, while the tree, as a whole, grows onward and upward.
This is what we see in the horse, which is the living representative of
an unbroken line reaching back to the little Eocene Hyracothere. So in
a general way it may be said that much of what at the first glance we
might term extinction is really the replacement of one set of animals by
another better adapted to surrounding conditions.
Again, there are many cases of animals, and particularly of large
animals, so peculiar in their make up, so very obviously adapted to
their own special surroundings that it requires little imagination to
see that it would have been a difficult matter for them to have
responded to even a slight change in the world about them. Such great
and necessarily sluggish brutes as Brontosaurus and Diplodocus, with
their tons of flesh, small heads, and feeble teeth, were obviously
reared in easy circumstances, and unfitted to succeed in any strenuous
struggle for existence. Stegosaurus, with his bizarre array of plates
and spines, and huge-headed Triceratops, had evidently carried
specialization to an extreme, while in turn the carnivorous forms must
have required an abundant supply of slow and easily captured prey.
Coming down to a more recent epoch, when the big Titanotheres
flourished, it is easy to see from a glance at their large, simple teeth
that these beasts needed an ample provision of coarse vegetation, and as
they seem never to have spread far beyond their birthplace, climatic
change, modifying even a comparatively limited area, would suffice to
sweep them out of existence. To use the epitaph proposed by Professor
Marsh for the tombstone of one of the Dinosaurs, many a beast might say,
"I, and my race perished of over specialization." To revert to the horse
it will be remembered that this very fate is believed to have overtaken
those almost horses the European Hippotheres; they reached a point where
no further progress was possible, and fell by the wayside.
There is, however, still another class of cases where species, families,
orders, even, seem to have passed out of existence without sufficient
cause. Those great marine reptiles, the Ichthyosaurs, of Europe, the
Plesiosaurs and Mosasaurs, of our own continent, seem to have been just
as well adapted to an aquatic life as the whales, and even better than
the seals, and we can see no reason why Columbus should not have found
these creatures still disporting themselves in the Gulf of Mexico. The
best we can do is to fall back on an unknown "law of progress," and say
that the trend of life is toward the replacement of large, lower animals
by those smaller and intellectually higher.
But _why_ there should be an allotted course to any group of animals,
why some species come to an end when they are seemingly as well fitted
to endure as others now living, we do not know, and if we say that a
time comes when the germ-plasm is incapable of further subdivision, we
merely express our ignorance in an unnecessary number of words. The
mammoth and mastodon have already been cited as instances of animals
that have unaccountably become extinct, and these examples are chosen
from among many on account of their striking nature. The great ground
sloths, the Mylodons, Megatheres, and their allies, are another case in
point. At one period or another they reached from Oregon to Virginia,
Florida, and Patagonia, though it is not claimed that they covered all
this area at one time. And, while it may be freely admitted that in
some portions of their range they may have been extirpated by a change
in food-supply, due in turn to a change in climate, it seems
preposterous to claim that there was not at all times, somewhere in this
vast expanse of territory, a climate mild enough and a food-supply large
enough for the support of even these huge, sluggish creatures. We may
evoke the aid of primitive man to account for the disappearance of this
race of giants, and we know that the two were coeval in Patagonia, where
the sloths seem to have played the rôle of domesticated animals, but
again it seems incredible that early man, with his flint-tipped spears
and arrows, should have been able to slay even such slow beasts as these
to the very last individual.
Of course, in modern times man has directly exterminated many animals,
while by the introduction of dogs, cats, pigs, and goats he has
indirectly not only thinned the ranks of animals, but destroyed plant
life on an enormous scale. But in the past man's capabilities for harm
were infinitely less than now, while of course the greatest changes took
place before man even existed, so that, while he is responsible for the
great changes that have taken place in the world's flora and fauna
during recent times, his influence, as a whole, has been insignificant.
Thus, while man exterminated the great northern sea-cow, Rytina, and
Pallas's cormorant on the Commander Islands, these animals were already
restricted to this circumscribed area[22] by natural causes, so that man
but finished what nature had begun. The extermination of the great auk
in European waters was somewhat similar. There is, however, this
unfortunate difference between extermination wrought by man and that
brought about by natural causes: the extermination of species by nature
is ordinarily slow, and the place of one is taken by another, while the
destruction wrought by man is rapid, and the gaps he creates remain
unfilled.
[22] _It is possible that the cormorant may always have been confined to
this one spot, but this is probably not the case with the sea-cow._
Not so very long ago it was customary to account for changes in the past
life of the globe by earthquakes, volcanic outbursts, or cataclysms of
such appalling magnitude that the whole face of nature was changed, and
entire races of living beings swept out of existence at once. But it is
now generally conceded that while catastrophes have occurred, yet, vast
as they may have been, their effects were comparatively local, and,
while the life of a limited region may have been ruthlessly blotted out,
life as a whole was but little affected. The eruption of Krakatoa shook
the earth to its centre and was felt for hundreds of miles around, yet,
while it caused the death of thousands of living beings, it remains to
be shown that it produced any effect on the life of the region taken in
its entirety.
Changes in the life of the globe have been in the main slow and gradual,
and in response to correspondingly slow changes in the level of portions
of the earth's crust, with their far-reaching effects on temperature,
climate, and vegetation. Animals that were what is termed plastic kept
pace with the altering conditions about them and became modified, too,
while those that could not adapt themselves to their surroundings died
out.
How slowly changes may take place is shown by the occurrence of a
depression in the Isthmus of Panama, in comparatively recent geologic
time, permitting free communication between the Atlantic and Pacific, a
sort of natural inter-oceanic canal. And yet the alterations wrought by
this were, so to speak, superficial, affecting only some species of
shore fishes and invertebrates, having no influence on the animals of
the deeper waters. Again, on the Pacific coast are now found a number of
shells that, as we learn from fossils, were in Pliocene time common on
both coasts of the United States, and Mr. Dall interprets this to mean
that when this continent was rising, the steeper shore on the Pacific
side permitted the shell-fish to move downward and adapt themselves to
the ever changing shore, while on the Atlantic side the drying of a wide
strip of level sea-bottom in a relatively short time exterminated a
large proportion of the less active mollusks. And in this instance
"relatively short" means positively long; for, compared to the rise of a
continent from the ocean's bed, the flow of a glacier is the rapid rush
of a mountain torrent.
Then, too, while a tendency to vary seems to be inherent in animals,
some appear to be vastly more susceptible than others to outside
influences, to respond much more readily to any change in the world
about them. In fact, Professor Cook has recently suggested that the
inborn tendency to variation is sufficient in itself to account for
evolution, this tendency being either repressed or stimulated as
external conditions are stable or variable.
The more uniform the surrounding conditions, and the simpler the animal,
the smaller is the liability to change, and some animals that dwell in
the depths of the ocean, where light and temperature vary little, if
any, remain at a standstill for long periods of time.
The genus Lingula, a small shell, traces its ancestry back nearly to the
base of the Ordovician system of rocks, an almost inconceivable lapse of
time, while one species of brachiopod shell endures unchanged from the
Trenton Limestone to the Lower Carboniferous. In the first case one
species has been replaced by another, so that the shell of to-day is not
exactly like its very remote ancestor, but that the type of shell
should have remained unchanged when so many other animals have arisen,
flourished for a time, and perished, means that there was slight
tendency to variation, and that the surrounding conditions were uniform.
Says Professor Brooks, speaking of Lingula: "The everlasting hills are
the type of venerable antiquity; but Lingula has seen the continents
grow up, and has maintained its integrity unmoved by the convulsions
which have given the crust of the earth its present form."
Many instances of sudden but local extermination might be adduced, but
among them that of the tile-fish is perhaps the most striking. This
fish, belonging to a tropical family having its headquarters in the Gulf
of Mexico, was discovered in 1879 in moderately deep water to the
southward of Massachusetts and on the edge of the Gulf Stream, where it
was taken in considerable numbers. In the spring of 1882 vessels
arriving at New York reported having passed through great numbers of
dead and dying fishes, the water being thickly dotted with them for
miles. From samples brought in, it was found that the majority of these
were tile-fish, while from the reports of various vessels it was shown
that the area covered by dead fish amounted to somewhere between 5,000
and 7,500 square miles, and the total number of dead was estimated at
not far from _a billion_. This enormous and widespread destruction is
believed to have been caused by an unwonted duration of northerly and
easterly winds, which drove the cold arctic current inshore and
southwards, chilling the warm belt in which the tile-fish resided and
killing all in that locality. It was thought possible that the entire
race might have been destroyed, but, while none were taken for many
years, in 1899 and in 1900 a number were caught, showing that the
species was beginning to reoccupy the waters from which it had been
driven years before.
The effect of any great fall in temperature on animals specially adapted
to a warm climate is also illustrated by the destruction of the Manatees
in the Sebastian River, Florida, by the winter of 1894-95, which came
very near exterminating this species. Readers may remember that this was
the winter that wrought such havoc with the blue-birds, while in the
vicinity of Washington, D. C., the fish-crows died by hundreds, if not
by thousands.
Fishes may also be exterminated over large areas by outbursts of
poisonous gases from submarine volcanoes, or more rarely by some vast
lava flood pouring into the sea and actually cooking all living beings
in the vicinity. And in the past these outbreaks took place on a much
larger scale than now, and naturally wrought more widespread
destruction.
A recent instance of local extermination is the total destruction of a
humming-bird, _Bellona ornata_, peculiar to the island of St. Vincent,
by the West Indian hurricane of 1898, but this is naturally extirpation
on a very small scale.
Still, the problems of nature are so involved that while local
destruction is ordinarily of little importance, or temporary in its
effects, it may lead to the annihilation of a species by breaking a race
of animals into isolated groups, thereby leading to inbreeding and slow
decline. The European bison, now confined to a part of Lithuania and a
portion of the Caucasus, seems to be slowly but surely approaching
extinction in spite of all efforts to preserve the race, and no reason
can be assigned for this save that the small size of the herds has led
to inbreeding and general decadence.
In other ways, too, local calamity may be sweeping in its effects, and
that is by the destruction of animals that resort to one spot during the
breeding season, like the fur-seals and some sea-birds, or pass the
winter months in great flocks or herds, as do the ducks and elk. The
supposed decimation of the Moas by severe winters has been already
discussed, and the extermination of the great auk in European waters was
indirectly due to natural causes. These birds bred on the small, almost
inaccessible island of Eldey, off the coast of Iceland, and when,
through volcanic disturbances, this islet sank into the sea, the few
birds were forced to other quarters, and as these were, unfortunately,
easily reached, the birds were slain to the last one.
From the great local abundance of their remains, it has been thought
that the curious short-legged Pliocene rhinoceros, _Aphelops fossiger_,
was killed off in the West by blizzards when the animals were gathered
in their winter quarters, and other long-extinct animals, too, have been
found under such conditions as to suggest a similar fate.
Among local catastrophes brought about by unusually prolonged cold may
be cited the decimation of the fur-seal herds of the Pribilof Islands in
1834 and 1859, when the breeding seals were prevented from landing by
the presence of ice-floes, and perished by thousands. Peculiar interest
is attached to this case, because the restriction of the northern
fur-seals to a few isolated, long undiscovered islands, is believed to
have been brought about by their complete extermination in other
localities by prehistoric man. Had these two seasons killed all the
seals, it would have been a reversal of the customary extermination by
man of a species reduced in numbers by nature.
In the case of large animals another element probably played a part. The
larger the animal, the fewer young, as a rule, does it bring forth at a
birth, the longer are the intervals between births, and the slower the
growth of the young. The loss of two or three broods of sparrows or two
or three litters of rabbits makes comparatively little difference, as
the loss is soon supplied, but the death of the young of the larger and
higher mammals is a more serious matter. A factor that has probably
played an important rôle in the extinction of animals is the relation
that exists between various animals, and the relations that also exist
between animals and plants, so that the existence of one is dependent on
that of another. Thus no group of living beings, plants or animals, can
be affected without in some way affecting others, so that the injury or
destruction of some plant may result in serious harm to some animal.
Nearly everyone is familiar with the classic example given by Darwin of
the effect of cats on the growth of red clover. This plant is fertilized
by bumble bees only, and if the field mice, which destroy the nests of
the bees, were not kept in check by cats, or other small carnivores,
their increase would lessen the numbers of the bees and this in turn
would cause a dearth of clover.
The yuccas present a still more wonderful example of the dependence of
plants on animals, for their existence hangs on that of a small moth
whose peculiar structure and habits bring about the fertilization of the
flower. The two probably developed side by side until their present
state of inter-dependence was reached, when the extinction of the one
would probably bring about that of the other.
It is this inter-dependence of living things that makes the outcome of
any direct interference with the natural order of things more or less
problematical, and sometimes brings about results quite different from
what were expected or intended.
The gamekeepers on the grouse moors of Scotland systematically killed
off all birds of prey because they caught some of the grouse, but this
is believed to have caused far more harm than good through permitting
weak and sickly birds, that would otherwise have fallen a prey to hawks,
to live and disseminate the grouse distemper.
The destruction of sheep by coyotes led the State of California to place
a bounty on the heads of these animals, with the result that in
eighteen months the State was called upon to pay out $187,485. As a
result of the war on coyotes the animals on which they fed, notably the
rabbits, increased so enormously that in turn a bounty was put on
rabbits, the damage these animals caused the fruit-growers being greater
than the losses among sheep-owners from the depredations of coyotes. And
so, says Dr. Palmer, "In this remarkable case of legislation a large
bounty was offered by a county in the interest of fruit-growers to
counteract the effects of a State bounty expended mainly for the benefit
of sheep-owners!"
Professor Shaler, in noting the sudden disappearance of such trees as
the gums, magnolias, and tulip poplars from the Miocene flora of Europe
has suggested that this may have been due to the attacks, for a series
of years, of some insect enemy like the gipsy moth, and the theory is
worth considering, although it must be looked upon as a possibility
rather than a probability. Still, anyone familiar with the ravages of
the gipsy moth in Massachusetts, where the insect was introduced by
accident, can readily imagine what _might_ have been the effect of some
sudden increase in the numbers of such a pest on the forests of the
past. Trees might resist the attacks of enemies and the destruction of
their leaves for two or three years, but would be destroyed by a few
additional seasons of defoliation.
Ordinarily the abnormal increase of any insect is promptly followed by
an increase in the number of its enemies; the pest is killed off, the
destroyers die of starvation and nature's balance is struck. But if by
some accident, such as two or three consecutive seasons of wet, drought,
or cold, the natural increase of the enemies was checked, the balance of
nature would be temporarily destroyed and serious harm done. That such
accidents may occur is familiar to us by the damage wrought in Florida
and other Southern States by the unwonted severity of the winters of
1893, 1895, and 1899.
If any group of forest trees was destroyed in the manner suggested by
Professor Shaler, the effects would be felt by various plants and
animals. In the first place, the insects that fed on these trees would
be forced to seek another source of food and would be brought into a
silent struggle with forms already in possession, while the destruction
of one set of plants would be to the advantage of those with which they
came into competition and to the disadvantage of vegetation that was
protected by the shade. Finally, these changed conditions would react in
various ways on the smaller birds and mammals, the general effect being,
to use a well-worn simile, like that of casting a stone into a quiet
pool and setting in motion ripples that sooner or later reach to every
part of the margin.
It is scarcely necessary to warn the reader that for the most part this
is purely conjectural, for from the nature of the case it is bound to be
so. But it is one of the characteristics of educated man that he wishes
to know the why and wherefore of everything, and is in a condition of
mental unhappiness until he has at least formulated some theory which
seems to harmonize with the visible facts. And from the few glimpses we
get of the extinction of animals from natural causes we must formulate a
theory to fit the continued extermination that has been taking place
ever since living beings came into the world and were pitted against one
another and against their surroundings in the silent and ceaseless
struggle for existence.
THE END.
INDEX
_The asterisk denotes that the animal or object is figured on or
opposite the page referred to._
Æpyornis, egg of, 145, 148,* 147, 157
eggs found in swamps, 148;
found floating, 148
eggs used for bowls, 145
origin of fable of Roc, 144, 145
Alaskan Live Mammoth Story, 190-193, 197
Anomoepus tracks, 39
Apteryx egg, 147
Archæopteryx, description of, 77, 78
discovery of, 77
earliest known bird, 70
restoration, 89*
specimens of, 70,* 88
wing, 72,* 73
Archelon, a great turtle, 54
Basilosaurus, 60
See also Zeuglodon
Beehler, L. W., 209, 213
Birds, always clad in feathers, 71, 127
earliest, 70
Birds, first intimation of, 76
rarity of fossil, 86, 87
related to reptiles, 92
wings of embryonic, 73
with teeth, 79, 88
Bison, European, 231
Books of reference, xix, 17, 32, 47, 69, 89, 110, 137, 158, 176,
197, 218
Breeding of large animals, 233
Brontornis, size of leg-bones, 149
Brontosaurus, size of bones, 96,* 97,* 109
Brooks, W. K., on Lingula, 229
Buffalo legend, 216
Buttons as vestigial structures, 202
Carcharodon auriculatus, 66
teeth, 66
megalodon, 65
estimated size, 66
teeth, 65, 67
Carson City footprints, 45
Casts, how formed, 10, 11
Cats and clover, 234
Cephalaspis, 24*
Ceratosaurus, habits, 106
restoration, 106*
skull, 110*
Changes in Nature slow, 227
Cheirotherium, 43
Chlamydosaurus, 129
Claosaurus. See Thespesius
Climate, changes in western United States, 174
Clover and cats, 234
Cold, effects of, on animals, 230, 231, 233
Cold winters, 230
Collecting fossils, 17, 112-116
Color of large land animals, 134
of young animals, 136
Covering of extinct animals sometimes indicated, 131, 132
Coyotes, effect of their destruction on fruit, 236
Dall, W. H., theory as to extinction of mollusks, 227
Dinosaurs, bones of, 109, 110
brain of, 93
collections of, 109
compared to marsupials, 95
first discovered, 90
food required by, 98
hip-bones mistaken for shoulder-blade, 120
Professor Marsh's epitaph for, 222
range, 92
recognized as new order of reptiles, 91
related to ostrich and alligator, 91
size of, 95, 96, 98
tracks, ascribed to birds, 38
Dinotherium, 200
Diplodocus, estimated weight, 99
supposed habits, 99
Egg of Æpyornis, 147, 148;
Apteryx, 147;
Ostrich, 146;
Moa, 148
Eggs, casts of, 87
Elephant, size, 180
size of tusks, 181, 182
Elephas ganesa, tusks, 196
Encrustations, 14
Extermination. See Extinction
Extinction, ascribed to great convulsions, 225
ascribed to primitive man, 188, 224
of Dinosaurs, 221
local, 225
by man, 224, 225
of Marine Reptiles, 222
often unaccountable, 222, 223
of Pliocene rhinoceros, 232
sometimes evolution, 221, 226
of Titanotheres, 222
Feathers, imprints of, 76, 132
Fishes, abundance of, 25
armored, 23, 24, 25, 28
collections of, 32
killed by cold, 230
killed by volcanoes, 231
Fish-crows, killed by cold, 231
Flesh does not petrify, 10
Flightless birds, absent from Tasmania, 155
present distribution, 154, 155
relation between flightlessness and size, 156
Folds and frills, 129
Footprints, collections of, 47
books on, 47
See also under Tracks
Fossil birds, rarity of, 86
Fossil man, 13
Fossilization a slow process, 10
Fossils, conditions under which they are formed, 5, 7
collecting, 112-116
definition of, 1
deformation of, 16
impressions, 2, 3
not necessarily petrifactions, 2
preparation of, 117-119
why they are not more common, 5, 15, 16
Fowls, muscles of, 81
Frill of Triceratops, 102
Fur-seals killed by ice-floes, 233
Gar pikes, destruction of, 26
Giant birds, reasons for distribution and flightlessness, 153
Giant Moa, 141
leg compared with that of horse, 152*
Giant Sloth, domesticated by man, 224
struggle between, 46
Giant Sloth, tracks at Carson City, 46
Gilfort, Robert, 157
Great Auk, extermination of, 232
Grouse on Scotch moors, 235
Hawkins, B. W., restorations by, 137
Hesperornis, description of, 80
impressions of feathers, 132
position of legs, 83, 84
restoration of, 82*
Hippotherium, 166, 167
Hoactzin, habits of, 74, 75*
Horn does not petrify, 130
Horse, abundant in Pleistocene time, 164
books on, 176
of bronze age, 163, 167
collections of fossil, 176
development of, 167, 168,* 175
differences between fossil and living, 163
early domestication, 165
evidence as to genealogy, 170-173
extra-toed, 172, 173
found in South America in 1530, 165
of Julius Cæsar, 172
none found wild in historic times, 165
Pliocene, 166
possibility of existence in America up to the time of its
discovery, 169, 170
primitive, 160, 161*
Horse, sketched by primitive man, 163
teeth of, 170
three-toed, 166
Humming-bird, exterminated by hurricane, 231
Hydrarchus, 62*
Hyracotherium, 160, 161,* 170, 174
Ichthyosaurs, silhouettes of, 132
Iguanodons, found at Bernissart, 104
Impressions of feathers, 131
of scales, 131
of skin, 131
Inbreeding, effects of, 231, 232
Information, sources of, xvi
Innuits, habits, 192
Interdependence of animals and plants, 234, 235, 238
Ivory, fossil, 2, 4, 188, 189
Jaw of Mosasaur, 54*
of reptiles, 53
Killing of the Mammoth, story, 177, 193
Kimmswick, deposit of Mastodon bones, 209
Knight, Charles R., restorations by, xviii, 136
Koch's Hydrarchus, 61, 62*
Missourium, 207,* 208
Leaves, impressions of, 3, 13
Leg of Brontornis, 149*
Leg of the Great Brontosaurus, 96*
of Giant Moa, 152*
position in Hesperornis, 83
position in ducks, 84
Lenape Stone, 215, 216, 219*
Life, earliest traces of, 21, 34
Lingula, antiquity of, 228
Professor Brooks on, 229
Loricaria, 24*
Mammoth, adapted to a cold climate, 134
Alaskan Live, Story, 190
believed to live underground, 178
bones taken for those of giants, 185
contemporary with man, 189
derivation of name, 178
description, 179
discovery of entire specimens, 183, 187
distribution, 184, 186
drawn by early man, 189, 197*
entire specimens obtainable, 194
reasons for extermination, 188
killing of the, 177
literature on, 197
misconception as to size, 179
mounted skeleton, 179
not now living, 190
preservation of remains, 187
skeletons in Alaska, 181, 195
Mammoth, in Chicago Academy of Sciences, 179
at St. Petersburg, 183*
restoration, 176*
size, 179, 180, 181
size of tusks, 181, 196
teeth, 196, 199*
teeth dredged in North Sea, 184
tusks brought into market, 188, 189
Man contemporary with Mammoth, 189
fossil, 13
of Guadeloupe, 13
Manatees killed by cold, 230
Marsh, Prof. O. C., collection of fossil horses, 176
on Dinosaurs, 222
on toothed birds, 79, 89
Mastodon, bones taken for those of giants, 205
thought to be carnivorous, 206
covering, 210
description, 210
distribution, 203, 210, 212
extinction, 212
literature, 218
and man, 215, 216
first noticed in America, 204
origin unknown, 202
remains abundant, 208, 209
remains in Ulster and Orange counties, New York, 204, 206
restoration, 210*
Mastodon, size, 211
skeletons on exhibition, 218
species, 203
teeth, 198, 199,* 218
tusks, 199, 200
Mesohippus, 167
Mimicry, not conscious, 128
Missourium of Koch, 207,* 208
Moas, collections of, 156, 157
contemporary with man, 143, 144
deductions from distribution, 143
destruction of, 143, 144
discovery of bones, 140
elephant-footed, 142
feathers of, 141
Giant, 141
supposed food of, 142
legends of, 139, 140
literature, 158
scientific names, 146
size of, 141
species of, 141
Moloch, an Australian lizard, 100*
Mosasaurs, abundance of, in Kansas, 52
books on, 69
collections of, 68
extinction of, 56
first discovery, 50
jaw of, 54*
Mosasaurs, range of, 49
restoration, 52*
size of, 49, 50
Mylodon tracks at Carson City, 45
Names, scientific, reasons for using, xvi, xvii
Nature, balance of, 238
Nuts, fossil, 11
Oldest animals, 21
vertebrates, 19, 22
Ostrich egg, 147
Over-specialization, 221, 222
Peale, C. W., 205
Peale, Rembrandt, 205, 206
Pelican, mandible, 53
Penguins, depend on fat for warmth, 127
feathers highly modified, 128
swim with wings, 80
Petrified bodies, 10
Phororhacos, description of, 149
mistaken for mammal, 149
Patagonian bird, 148
related to heron family, 152
restoration, frontispiece
skull, 150, 151*
Protohippus, 166
Pteraspis, 28
Pterichthys, 25, 28, 32*
mistaken for crab, 25
Pterodactyls, impressions of wings, 133
from Kansas, 55
wing, 72*
Pycraft, W. P., restoration of Archæopteryx, 89
Radiolarians, 15, 17*
Reconstruction of animals, 127, 130, 134
Reptiles, fasting powers of, 98
growth throughout life, 102
jaws, 53
Restorations, xviii
Archæopteryx, 89*
Ceratosaurus, 106*
Hesperornis, 82*
Mammoth, 176*
Mastodon, 210*
Phororhacos, frontispiece
progress in, 137
Stegosaurus, 108*
Thespesius, 90*
Triceratops, 126*
Tylosaurus, 52*
Reversion of fancy stock, 171
Rhinoceros, exterminated by cold, 232
Roc, legend of, 144, 145
Rocks, thickness of sedimentary, 20
Ruffles on dresses, 202
Schuchert, Charles, on collecting fossils, 17
collector of Zeuglodon bones, 63
Seals, covering of, 128
Sea-serpent, belief in, 56
possibility of existence, 57
Shaler, Professor, on changes in Miocene flora of Europe, 236, 237
Sharks, early, 31
Great-toothed, 65
known from spines and teeth, 29
Port Jackson, 29
teeth of, 69
White, or Man-Eater, 65
Skeleton, basis of all restorations, 127
best testimony of animal's relationships, 124
information to be derived from, 120, 122, 123, 124, 125, 126, 127
a problem in mechanics, 102, 124
reconstruction of, 120
relation of, to exterior of animal, 121, 127
of Triceratops, 103,* 121
Spines and plates, 130
Stegosaurus, description of, 106
restoration of, 108*
Survival of the fittest, 173
Teeth, birds with, 79
of gnawing animals, 169, 200
of grass-eaters, 169
Teeth, of horse, 170
of mammoth, 198, 199*
of mastodon, 198, 199*
of sharks, 29, 30
of Thespesius, 105
Thespesius, abundance of, 104, 105
brain of, 93
(Same as Claosaurus)
engulfed in quicksand, 8
impressions of skin, 132
restoration of, 90*
teeth of, 105
at Yale, 109
Tiger, preying on reindeer, 134
Tile-fish, destruction of, 230
Titanichthys, 28, 29
Toothed birds, collections of, 88
discovery of, 79
Townsend C. H., 190-192
Tracks, ascribed to birds, 38
ascribed to giants, 45
animals known from, 41
collections of, 47
of Connecticut Valley, 37
deductions from, 44
of Dinosaurs, 38,* 40,* 41, 47*
discovery in England and America, 37, 42
how formed, 35, 40
at Hastings, 44
Tracks, of Mylodon, 46
of worms, 3, 33
Triceratops, brain, 94
broken horn, 102
description, 100, 101
restoration, 126*
skeleton, 103*
Tufa, 14
Tukeman, killing of the Mammoth, 177, 193
Variation in animals, 228
Vertebrates, oldest, 22
Vestigial structures, 201, 202
Volcanic outbursts, 231, 232
Webster, F. S., on destruction of gar pikes, 26
White, C. A., on the nature and uses of fossils, 17
White Shark, 65
Wings, 71, 72,* 73
of embryonic birds, 73
Wood, fossil, 9, 10
Worm trails, 3, 33
Yucca, fertilization, 235
Zeuglodon, abundance of remains, 60
same as Basilosaurus
description, 58, 63
habits, 59
Zeuglodon, Koch's restoration, 62
name, 58, 69
once numerous, 60
size, 58
specimen of, 68
structure of bones, 64
teeth, 58, 69*
End of Project Gutenberg's Animals of the Past, by Frederic A. Lucas
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