vegetable life on our Earth. We will go back to the coal for a moment
and see what the animal life of that time was. The seas of the time of
the coal forests were sometimes shallow, sometimes deep, and in the
limestone rocks of the oceans which separated the great continents of
that time there is a record of the inhabitants of the seas. The land
plants were of more than 1,000 different kinds, and there were more
than 200 kinds of fishes in the waters, and corals, shells, and small
crab-like animals innumerable. The fishes were fellows with terrible
teeth, and their bodies were covered with strong hard scales. One of
these fish was thirty feet long, and there were others of considerable
size. It is curious that the fishes of this time remind one of reptiles
(lizards and crocodiles), just as the birds of a future time seem to
have something of the reptile about them, as you will see by-and-by.
I dare say you have remarked while reading that all the plants and
animals of the early ages of the world seem to be made on a simple
plan, and as the Earth grows older they become more perfect, and this
is just what I want you to take notice of all through. The plants
of the coal period, you have seen, were nothing like so perfect in
construction, beautiful as they were, as the forest trees of the
present time, neither were the animals so perfect as those living now.
There has been _progress_, step by step, throughout the vegetable and
animal creation; and, though many of the lower forms of the early ages
exist now, there are others far superior to them which did not exist
then: but all this will come in “The Animal Part.”
About the middle of the Earth’s age came the wonderful period of
vegetation which gave us our coal, and after that there was a great and
busy time, when huge reptiles and reptile-like birds, and then true
birds, made their appearance. But that belongs to the next part of the
“puzzle of life.”
If we look with astonishment at the coal forests, we may also well
think of them with thankfulness. Here is the sunshine of past ages
stored up for our use, and we bring it out again to warm ourselves,
cook our food, make all our iron things, and drive our steam-engines!
Can any romance be finer than this, that we are carried across to
America and India and Australia in steam-boats driven by the “fossil
sunlight” of ages and ages past, and whirled along at sixty miles an
hour over iron rails by the same stored-up strength?
If you doubt this, think of living trees. Do they not live by the air
and sunlight? Will they grow without these? They spread their branches
and leaves to gather the warmth and light from the air, and when they
are cut down and dried, and you put a match to the wood, all the old
warmth and light come out again; and we know that the coal is only
fossil wood. Our Creator wastes nothing. Even when there were no people
living to rejoice in the sun, He thought of those people who _should_
come in time, and not one of the fiery rays of the fierce sun was lost.
These mighty forests were sent to gather it, and when they had died
down they sank below the surface and were covered from the air, that
none of their light or heat should escape.
In such forests it is strange that there were no birds, especially as
there were swarms of insects, and no doubt abundance of worms. But no
bone of bird or any trace of feathered songster of these lovely groves
has yet been found. Little lizards chased flies and beetles up and down
the stems of the club-mosses and ferns, and larger reptiles lurked in
the long damp grass under the shade. The pools and ponds were filled
with curious fishes, and reefs of beautiful white coral fringed all the
shores of the seas.
But the Earth was not fit for the habitation of man. The fruits of the
trees were not such as he could have eaten, and their wood was not hard
enough to build houses of. Still it was being got ready for him, and
not a leaf waved uselessly in the bright, warm air, and not a tree fell
to the ground, but it was to be turned into coal, and to come forth
again one day a hard black lump, without any of its former beauty, but
to give back the light and heat it had gathered from the sun ages and
ages ago.
Many periods in the Earth’s history have passed since the coal period,
and in every one of these the trees have been increasing in perfection,
though there have never since been such great numbers of a few kinds
growing. When we come to the more lately formed beds of earth we begin
to find the cypress, willow, ash, oak, elm, and other forest trees
which are living now. The trunks of these trees, blackened by age, lie
buried in peat bogs and swamps all over Europe. The mighty Mississippi
river brings down immense quantities of dead trees, and as these sink
to the bottom near its mouth they are forming future coal beds. Along
the coast of Norfolk and Suffolk, too, and stretching far away under
the German Ocean, is an old English forest. In some places the trunks
of the buried trees may be seen standing upright just where they grew.
The nets of the fishermen are continually bringing up pieces of wood,
roots, and seeds; and when the sea washes away the soft cliffs here the
bones, teeth, and tusks of the elephant, rhinoceros, hippopotamus, and
other large animals which inhabited this forest, may be seen in great
numbers.
Down below the waves of ocean have these woods sunk with all their once
living creatures, and though you may suppose that it must have been
very long ago that they grew, they are of the same kind as those which
now make the hills and valleys of England beautiful.
Sometimes a forest must sink very fast, for travellers have told us how
they have sailed on rivers and lakes over the tops of sunken trees,
and, looking down into the clear water, have seen the branches waving
below—tall trees standing upright at the bottom, and the boats sailing
over their tops!
We must now pass on to the living creatures which peopled the Earth,
and their story can be told with more certainty than that of the
perishable plants which clothed the surface of the ground, and, while
they rendered it beautiful, also served as food and shelter for
innumerable animals, and have become so useful to us as coal, lignite,
black-lead, and other productions of ancient forests.
FOOTNOTES:
[1] Specimen in Table-case 15, Room V., North Gallery British Museum.
[2] The name _Eophyton_ has also been suggested for the earliest
vegetable forms.
[3] Divisions A and B of Case 1, Room I., North Gallery, contain some
of the oldest known fossil plants.
[4] Fossil insects in Table-case No. 14, Room V.
[5] In 81° 44′ N. latitude.
[6] Specimens of plants from the coal in Cases No. 2, 3, 4, in Room I.
_THE ANIMAL PART._
We must now go back and collect the smaller pieces of “the puzzle”
which make up the animal part. The great periods of vegetation ended in
our country with the coal forests, and there has been no such wonderful
growth of plants since the time when the New Red Sandstone, lying above
the coal, was formed; though no doubt trees and plants have since
flourished, as they do now on the Earth, but not in such quantities as
during the coal period.
We remember that the eozöon, “the life-dawn animal,” is the oldest
animal we know of, and that it lived so long ago as when the Laurentian
rocks were laid down at the bottom of the seas of that time; then in
later rocks we find the burrows of sea worms in the stone, and later
still simple shells with two valves like the common mussel, and other
animals of a simple kind, like the corals, sponges, and star-fishes
which exist now. There must have been millions of these creatures in
the older limestone seas, for the rocks are almost entirely composed
of their fossil shells and bodies. By-and-by a rather superior animal
inhabited the seas of Wales, called a trilobite, of which you will see
a picture on the opposite page. This curious animal was of the same
family as the shrimps and prawns, but much larger, and he must have
been a giant among the others. None of these animals had any bones, you
must understand; but they had a hard shelly covering to support their
soft bodies inside, and no doubt the trilobites were able to swim about
very fast.[7]
[Illustration: III.
_Trilobite._]
What I want you to take notice of now is the _progress_ that has been
going on from the almost motionless eozöon to the shell-fish and
star-fish, which could crawl along the bottom of the sea and over the
rocks, to this active, quick-moving trilobite, with his great paddles.
Then the next step is a very great one, when we come to animals with
bones. The first of these are fishes. All the other bones are joined to
the backbone, therefore all animals with bones are called _vertebrata_,
which is a Latin word meaning having a backbone with joints. Now
animals with bones are plainly superior to those with only shells, and
when we find fishes among the rocks of Wales and Devonshire we know
that we are beginning to pick up some important pieces of the “puzzle
of life.” These fishes were most of them related to the sturgeon, and
their bones and teeth are found in great quantities in the Old Red
Sandstone rocks, just below the coal.[8]
It is not until we get above the coal into the oolite or egg-stone
rocks that still larger and altogether superior animals, both of sea
and land, began to increase, and this is called
THE AGE OF REPTILES.
This has been called the reptile age because there were such numbers
of animals like crocodiles, lizards, and tortoises (which are all
reptiles), and some of them were of immense size. For instance, there
was a huge creature something like a frog, but as large as a Shetland
pony, called the _Labyrinthodon_, with a great many curious teeth, and
this animal has left footprints in the New Red Sandstone which have
been dried and buried, we can’t tell how long, and there are the cracks
made by the sun drying the place he walked over when that was soft
earth. There is a drawing of some of these footsteps in the picture on
the next page, and there are also the footprints of a large bird, and
you can see where he walked over the soft earth and made a long line of
footmarks; and if you look at the footprints of birds on the snow or
mud now you will notice marks just like these. Then there is another
picture of a single footprint of a large bird, and all those round dots
are where rain-drops fell and left their marks in the soft earth.
[Illustration: IV.
(1) _Footprints of Labyrinthodon._
(3) _Footprints of Birds_, (2) _with marks of Rain-drops_.]
I dare say you will wonder how it is that these footprints have not
disappeared. Well, when the animals and birds that made them had
gone the marks became filled with dry sand, no doubt blown in by the
wind, and then the mud dried hard, and at last it became covered with
other earths and sank slowly down, just as the coal forests had done
before, and remained there until we dug it up with these tracks of
the birds and animals that lived then. Some of these birds must have
been larger than any living now, because their footmarks are so long.
None of their bones have been found yet, I believe, but plenty of the
teeth and some bones of the labyrinthodon have. The real footmarks, of
course, are very large, though they are small in the picture.[9]
In the great beds of Lias there are many other strange animals, and
among them are two great fish-lizards called the _Ichthyosaurus_
and _Plesiosaurus_. Both of these lived in the water and perhaps
came on land sometimes, and it is certain that they must have been
very ferocious creatures, from their great size and sharp teeth. The
plesiosaurus would be able to raise his long neck above the water and
snap at some of those curious birds rather like bats which lived at the
time, and of which I shall have something to say presently. Some of
these fish-lizards were as large as whales, and their bodies have been
so beautifully preserved in the limestone rocks that we can actually
sometimes find in their stomachs the food they lived on.
[Illustration: V.
_Ichthyosaurus._
_Plesiosaurus._
FISH-REPTILES.]
Now we have got to a higher order of creation still, these
fish-lizards, and they remind one of the next step in progress—birds.
You know that all birds lay eggs, so do almost all reptiles, such as
crocodiles, lizards, and most snakes, so that they are alike in this.
Then the plesiosaurus with his long neck reminds us of such birds as
the heron and the swan, but he is altogether more like a reptile than
either a fish or a bird. There were also huge land reptiles, which
lived in the forests of the time, and must have been a terror to the
smaller animals. From the bones of one of these which have been found
in the oolite clays near Weymouth in Dorsetshire (the _Cetiosaurus_),
we see that it must have been nearly as large as an elephant, and
there are others called the _Megalosaurus_, _Dinosaurus_, &c. All these
names end with _saurus_, a name taken from the Greek word meaning
lizard; and you will see now why the oolite, or “Jurassic”[10] age,
as it is sometimes called, is well named the “reptile age,” for these
creatures swarmed on the land and in the sea. Specimens of these you
can see for yourselves in the cases on the walls of the third room in
the North Gallery of the British Museum, where all the fossils are
collected.
But still more extraordinary animals than any of these lived at the
time, and we can scarcely tell whether they were birds or reptiles, as
they were something like both, but I suppose we must call them flying
reptiles, and they are the nearest approach to birds that had yet
existed. These creatures are called _Pterodactyles_, from two Greek
words which mean “wing-fingered.” Suppose the little fingers of both
your hands were a yard longer than the others, and suppose a thick
leathery skin was stretched from the tips of your long little fingers
to each of your feet, you would have wings something like a pterodactyl
and also something like the wings of a bat. But the pterodactyl had a
long neck and a long beak-like mouth, full of long sharp pointed teeth.
It could not walk much I think, but it could hang itself up by its hind
limbs to a tree or rock, head downwards like a bat, and must have been
able to fly very strongly, with its huge leathery wings, but it had no
feathers. There were swarms of these curious half lizard half bird-like
animals on the land, and they were of all sizes, some no bigger than a
crow, and some as large as the albatross, measuring twelve feet across
their outstretched wings. Their skeletons are some of the commonest
fossils in the oolite rocks, all through the great reptile age.[11]
Now you see we have come to a reptile that can fly, but, excepting for
its wings and some of its bones, more like a crocodile than a bird. A
little further on we find another curious animal in the oolite rocks,
which is much more like a true bird than the pterodactyl, because it
had feathered wings. It is called the _Archæopteryx_, which means
“ancient wing,” and I have given a picture of it on the same page as
the pterodactyl, so that you may compare them together. The blade-bone
and “merry-thought” of this creature were exactly like those of a bird,
and so were the feet and legs, which would enable it to walk easily, or
perch on the branch of a tree, but the tail was long and many-jointed
like that of a lizard, with a fan of feathers growing on each side
of it, and short feathered wings. Then it most likely had teeth like
a lizard, and there were short claws at the bend of the wings. This
bird-reptile was about the size of a crow, and was the first we know of
with feathers, and the limestone rock has preserved it most beautifully
through all the long ages which have passed since it flitted over the
land of the oolite period.[12] Later still than these, there lived in
America, about the time the chalk was formed in England, two strange
birds called _Hesperornis_ and _Ichthyornis_, both of which had teeth
in the jaws. The former was an immense fellow like the penguin, with
short wings, and the latter was about the size of a pigeon with large
feathered wings.
They are finding more of these curious creatures every now and then in
America. Some are without teeth, and have a horny bill like that of a
real bird, and in other ways more nearly resemble living birds; still
they have not lost the appearance of reptiles in their principal bones.
[Illustration: VI.
_Pterodactyl_ (_Wing-finger_).
_Archæopteryx_ (_Ancient-wing_).]
I have been particular in describing some of these fish-lizards
and bird-reptiles; because they, or their near relations, were the
principal inhabitants of land and sea from the end of the coal period
to the end of the chalk, though there were of course swarms of fishes
and shell-fish; but I ought to tell you that even so early as this
there was at least one animal known which suckled its young ones, and
this was a small insect-eating creature not larger than a rat, of the
same family (called _Marsupial_) as the kangaroo of Australia, which
carries its young ones in a pocket or pouch in its skin.
All this time we have been hunting for parts of “the puzzle” in those
ancient oolite rocks between the coal and the chalk, and those we
have found are very important. We have seen the slow progress from
simple sea shells to simple fishes, and then onwards to fish-lizards
and bird-reptiles with one little marsupial animal, of a far higher
kind, in between, as if to tell us beforehand what more complete and
perfect animals we might expect by-and-by. After the fishes we have
found fish-lizards, then bird-reptiles with wings, but no feathers, and
later still a bird-reptile with wing and tail feathers. How different
the life of the Earth was at the end of the “reptile age” of the oolite
rocks, to the far back Laurentian time when one little creature, our
old friend eozöon, alone held possession of the seas!
THE CRETACEOUS PERIOD.
Now let us look into the rocks next above, and see what is to be found
there. We have arrived in the Cretaceous period, or time when the
chalk was formed.[13] You remember I told you you might call this
“foraminifera earth” because so much of it was made up of the shells
of these tiny animals, thousands of which could be put into a thimble.
Whenever you make a mark with a piece of drawing chalk you rub off a
number of them, and you will see what pretty little creatures they
were if you look at the drawings of some of them on the next page as
they are seen under the microscope, magnified thousands of times their
natural size; but there are others of different shapes. On the same
page too there is a handsome shell, called an ammonite, and of its real
size, common in chalk rocks. The seas of the time must have been very
deep as I have explained before, and the chalk contains numbers of
bones of fishes everywhere, and many of the remains of the reptile-like
creatures of the time before. Corals, sea-urchins, crabs, &c.,
abounded, and as you can scarcely ever see chalk without immense flint
stones in it, you may suppose what millions of sponges lived on the
rocks, for these flints are partly made up of their fossil bodies.[14]
Another Cretaceous period is beginning now at the bottom of the
Atlantic and Pacific Oceans, where it is deep enough to cover the Alps,
for these little foraminifera are living on the surface in countless
millions, and day by day their fossil shells are settling down to the
bottom and forming a soft grey mud, full of the carbonate of lime like
chalk. The climate of the Cretaceous age was mild and pleasant, as we
know from the kind of animals in the seas. Slowly the water began to
get shallower and shallower by the upheaval of the bed, and at last the
bottom of this mighty chalk ocean came up to the light and sun, to be
covered in some places with the drift and worn particles of older rocks
swept over it by rivers, and to receive new plants and new animals, and
in some places to remain almost bare, as it is on the downs of Brighton.
[Illustration: VII.
FOSSILS OF THE CHALK.
1 _Ammonite._
2 3 4 _Foraminifera_ (_Chalk-builders_).]
Now we take one more step upwards into almost a new world—the world on
which mighty animals lived, and which man came to share with them.
THE TERTIARY PERIOD.
The reign of the reptiles is now passed. The ichthyosaurus and
pterodactyl no longer inhabited the seas and continents. Great changes
had taken place in the shape of the land. A river larger than the Rhine
swept majestically through England from the borders of Wales right out
into the German Ocean, and its banks were covered with forests and
marshes, where the new animals which had come to take possession of
the earth lived and moved and had their being. The mountains of the
Pyrenees were raised above the sea, and parts of Surrey and Sussex
appeared too. It was most likely in the early part of the Tertiary
period that the stone was formed of which almost all Paris is built.
Fancy a great city built of the shells of dead animals! One can
scarcely believe it: but the microscope lets us into this secret of
Nature. If we take a piece of this stone and examine it in a powerful
microscope we see that it is made almost entirely of tiny shells, so
small that myriads of them could be packed in a nut-shell. How long
must they have been working to make all the stone beds of which Paris
is built? We cannot measure the time, we can only know it must have
been enormous!
All kinds of animals both of sea and land increased in numbers and
perfection. The ammonites were dead, but their even more beautiful
relation, the nautilus, was living as it is now. The trilobite was
gone, but his next relation, the lobster and crab, appeared. Fishes
abounded. Whales which suckle their young ones appeared, and the
numbers of vertebrata, or animals with backbones, were more numerous
than they had ever been before. Just as animals with bones are more
perfect than those with only skins or shells, so animals which suckle
their young ones are more perfect than those which only lay eggs.
Thus the whale is a more perfect animal than the shark, though both
inhabit the water; and elephants and even rats and mice more perfect
still; and because there were so many of these “sucklers,” or mammalia
as they are called, in the Tertiary period, we know that all living
creatures were becoming more perfect. It will interest you too to learn
that monkeys began to appear now, and that they were common in France,
while at the present time the only part of Europe where they are to be
found is on the rock of Gibraltar.
But I want particularly to tell you of the giant animals—the Mammoth,
Mastodon, Megatherium, Dinotherium, and others, and first let us see
what the mammoth was like.
In former times, when people accidentally found the bones of these
animals, they actually thought they had belonged to giant _men_, and
we can scarcely wonder at that: but we know better. If only one small
bone is shown to Professor Owen or Professor Huxley, he can tell at
once whether it belonged to a man or an animal, a fish or a bird, and
very often the particular animal too. Well, the bones of the mammoth
were found in the north of Russia on the banks of the river Lena in
1800: but the Russians knew of them before that, and the name they
gave the animal means “earth,” because they supposed it burrowed in the
earth like a mole. This one is now in the Museum at St. Petersburg, and
its brownish coat and long black hairs, and even the hoofs and some of
the flesh, can be distinctly seen. The drawing in the frontispiece is
taken from it. It was strange that any people could have supposed that
this huge creature, larger than an elephant and with great curved tusks
ten feet long and weighing 160 lbs., could have got underground of its
own accord: but that was the only way in which they could account for
finding it buried in the earth on the banks of the rivers. Look at
the picture in the frontispiece; what a splendid animal he was, this
old elephant; larger and stronger than any living elephants! Immense
quantities of their bones are found in Siberia, and the tusks and teeth
are brought in ship-loads to England, where they are sold for their
ivory. Their skeletons have been found in most countries of Europe, in
many parts of Asia, and in North America, and these animals must have
been common at one time near London, for their bones have been dug up
in the brick earth at Ilford in Essex and other places near the Thames.
There is a skull with tusks set up with iron supports in the British
Museum.[15]