LIVING CREATURES OF PAST AGES
Curious ideas about fossils—The pages of the Earth's history—Interesting finds within
the Earth—The ancestors of the horse—The ancestors of the birds—Gigantic reptiles
rule the Earth—Life when the coal-fields were being laid down—Abundance of
fish—Curious extinct fish—Poverty of life in lowest deposits—The origin of life
 MOTHER EARTH can be the only historian of the early life which existed in the oceans and on her surface long
before the arrival of man upon this planet.
In the preceding chapter we have seen that the discovery of fossils is not of recent date. The
ancients found fossil shells and fossil fish, and some of the earlier philosophers really discovered
the meaning of these. So long ago as two thousand five hundred years the presence of these buried
fossils was declared to be a proof that those portions of the Earth had formed the bed of an ocean
at some earlier date. At the same time many ancient writers had very fantastic ideas concerning the
Earth. However, there were books written upon the subject of fossils before the dawn of the
Nearly two thousand years after the declarations of the early philosophers (to be more exact, in the
fifteenth century) there arose great disputes concerning fossils. Some scientists argued that
fossils were merely freaks of nature, while others even suggested that they were carved stones,
 Other philosophers, whom we know to have been in the right, declared that the marine organisms that
had lived in the shells had inhabited the ocean exactly where the shells were buried. These disputes
were not settled easily, and long after geologists were convinced of the origin of fossils, the
facts were disputed from the religious side, these wranglings being still in evidence in the days of
The different layers of geological deposit may be regarded as the different pages of the Earth's
history. The deposits nearer the surface are naturally the later pages, while the deeper layers give
us the earlier history.
Our present object is to consider what has been discovered concerning the early life upon this
planet. It is fortunate that it is not necessary to dig down into the different deposits in order to
read this history. If this had been necessary we should never have been able to open anything but
the later pages; the lower deposits would have remained a sealed book. The book has opened of itself
at a great many places, for as mentioned in the preceding chapter, the lower strata have been forced
to the surface and project through the outer crust. It does not matter if the layers are no longer
in a horizontal position; their relative position is perfectly clear, and that is all we require.
Turning the pages of this great history backwards, we are not surprised to find that the fossil
remains which have been discovered in the uppermost deposits are well represented by living animals
with which we are familiar. We find among these the fossil remain l of lions, bears, wolves, horses,
dogs, deer, reindeer, bisons, camels, hares, weasels, mice, and such-like. From the discovery of
these we learn
 that all these contemporaries of ours lived also in ages long past.
We find also the fossil remains of existing birds, such as the eagle, goose, duck, pigeon, ostrich,
and so on. But in addition to all these we find the remains of some gigantic animals similar to the
elephant, but now quite extinct. Traces of these "mammoths" or woolly elephants are found sometimes
not very far from the present surface of the Earth. Men, busy digging the foundations of buildings
in some of our large cities, have discovered the fossil remains of extinct animals. In Australia the
uppermost layers show that kangaroos were at one time twice as large as at present.
It will be understood that even some of these later pages of the Earth's history take us back a few
million years. We have seen that among these deposits we find horses very similar to our
domesticated friends of to-day, but as we go to deeper layers we find horses with three toes on each
foot, only the centre toe being capable of touching the ground. Still lower we find that their
ancestors had as many as four toes, all capable of resting on the ground, but these horse-like
animals are no bigger than a child's rocking-horse of small size. Lower still we find the fossil
remains of a more primitive horse, no bigger than those toy horses which very little children
delight to pull along the nursery floor. But we must not picture a miniature horse such as the toy.
This small ancestor of the horse, measuring about one foot in height, was considerably different in
appearance from the horse as we know it to-day. His head and neck were shorter, and his back was
curved upwards, yet his fossil remains show quite clearly that he was a direct ancestor of the horse
of to-day. The words "direct ancestor" are
 used here in a different sense than in such terms as "our great-great-great-grandfather"; this
ancestor of the horse lived some millions of years ago, long before man inhabited the Earth. By
means of other fossil remains we can trace the ancestry of the elephant, the pig, the rat, and many
other classes of animals.
Among the fossils of these uppermost deposits, we find a great abundance of fish, serpents,
crocodiles, and tortoises. In addition to the ordinary birds, already mentioned, we find some
extinct birds with traces of teeth, and still lower down we find birds with teeth. In this turning
back of the Earth's history book we have already reached a time some millions of years ago.
If we continue the downward search for birds, we find some strange-looking specimens, not only armed
with teeth, but having three claws at the corner of each wing, and although they have feathered
coats they possess long lizard-like tails. These strange birds are not large, being about the size
of an ordinary pigeon. Some of the birds had no wings, and evidently swam about on the waters all
their lives. Continuing this search backwards, and keeping a look-out for fossils of birds, we find
that earlier than this period there were no real birds. There are complete skeletons of what can
only be described as flying lizards. These have no feathers, and their bat-like wings, when spread
for flight, must have measured in some cases as much as twenty feet from tip to tip. Some of these
flying reptiles grew to an enormous size; some authorities estimate them at sixty feet from the
point of the nose to the end of the tail. The sitting-room in an average dwelling-house is only
about twenty feet, so that one may gather a fair idea of the
 size of these flying reptiles. When we remember that reptiles keep on growing as long as they live,
we have only to presume a very long life for these creatures to enable them to reach such
proportions. In the deposits of an earlier date we find no sign of birds, and it is clear that their
earlier ancestors were true reptiles. By this time we have reached a very remote period.
MODEL OF THE DIPLODICUS COMPLETED
THIS IS THE MODEL SHOWN UNDER CONSTRUCTION. THIS GIGANTIC REPTILE OF LONG AGO WAS A VEGETARIAN,
AND PERFECTLY HARMLESS. HE MEASURED EIGHTY FEET IN TOTAL LENGTH.
Before that time we have lost trace of any forms of apes, which had become more and more primitive
as we descended. We find only traces of mammals, or breast-animals. We still find reptiles which, of
course, are egg-laying animals, and do not suckle their young as the mammalians do. The reptiles in
these lower deposits are the largest ever known. Some excellent skeletons of these have been
discovered, and with the knowledge obtained from these Dr. Carl Hagenbeck, of Hamburg, has made
life-size models representing the actual creatures.
In the illustration facing page 58 we see one of these models under construction, and this picture
gives us a good estimate of the size of the great creature. In the illustration facing this page we
see the complete model as it stands in the Hamburg Tierpark. This "Diplodocus," which measures
eighty feet in length, is not the largest animal of that period. It was a very harmless vegetarian,
whereas there were gigantic land animals, such as the "Allosaurus," seen in the illustration facing
page 62. Some of these land animals had powers of destruction which must have put terror into the
lives of the smaller creatures living within their reach. Of course, there are living animals of
to-day with huge bodies, such as the elephant, the hippopotamus, and the whale.
It seems probable that during the period when reptiles
 ruled the Earth the land became so crowded that some land animals had to take to the sea as a
dwelling, while others took to the air, very gradually evolving wings, until their descendants
became more birds than reptiles.
Still farther back we find reptiles of a much clumsier make, and it is apparent that some of them
had paddles to propel them through the water. These were preceded by similar reptiles, but having
feet in place of paddles, the feet being evolved into paddles when the animals left the land for the
surface of the sea.
Still farther back we find abundance of amphibious creatures, capable of living under the water or
on dry land as they desired. We may think of them as frog-like animals. During this period there was
a comparative scarcity of animal life.
Below this we come upon the great coal-beds of the world. From what has been said, at the close of
the preceding chapter, of the heated moist atmosphere, we are not surprised to learn that there were
plenty of snake-like creatures which could live in the swamps of the gigantic forests. There were
present also a great variety of shark-like creatures and lung-fish. There are fossils of land snails
which probably made their homes on the trees, while there is evidence of spiders, beetles, and other
insects that could live in a watery atmosphere. The gigantic vegetation was of a simple form, with
large leaves measuring about twenty inches across. But even with this enormous growth of vegetable
life the great accumulations required to form the coal-beds must have taken many thousands of years
Lower down than the coal-beds we find fish more abundant than ever. Some of these are as long as
 and are provided with jaws of enamelled bone, which evidently could be used like shear-blades. Fish
are said by some never to reach an adult size, but, like the reptiles, they grow till death. The
humorist might add that in our own days the fish caught by some enthusiastic anglers continue to
grow even after death.
A FEROCIOUS PRE-HISTORIC CREATURE
THIS IS THE PHOTOGRAPH OF THE LIFE-SIZE MODELS WHICH DR. CARL HAGENBECK HAS ERECTED IN TEH
TIERPARK AT HAMBURG. THIS HUGE "ALLOSAURUS" MUST HAVE BEEN A TERROR TO THE OTHER ANIMALS LIVING WITHIN HIS REACH.
Along with these early fish we find gigantic crabs, some measuring six feet across, and as we go
farther back we find fish protected on the head and shoulders with plates of bone. Still lower down
we discover fish completely armoured in this fashion, and it is interesting to know that our
contemporaries, the sea-urchins, had direct ancestors living away back in those far-off times. We
have proof that there was some land vegetation at that time, as there are fossil remains of insects.
In our backward search we come across even more primitive types of plated fish, and an abundance of
a very simple form of crab-like creatures, which we call "Trilobites." These were strange-looking
creatures, some measuring about two feet in length, and having their bodies divided into three
lobes. They had eyes, and could move or roll about. A few descendants of these are found as high up
as the coal-bed period, but it is in the lower deposits that they are plentiful, even when there are
no traces of fish at all, not even the simple forms of boneless fish, unless that class which we
describe as star-fish.
In these lower deposits we find no trace of land animals, not even insects, and from this we gather
that what land there was above water was probably too barren to support animal life. In the lowest
deposits we find no traces of life. But the first forms of life would be of soft, jelly-like
material, and would leave no record.
 In the address of Professor Schafer at the Dundee meeting of the British Association in 1912, he
dealt exhaustively with the subject of the origin of life upon this planet. His belief is that life
was evolved very gradually from lifeless matter, and that its first appearance would be as a mass of
colloidal slime, which could assimilate other matter and therefore grow, and by subdividing it could
reproduce itself. But these philosophical conceptions of the origin of life are without the scope of