The puzzle of life, and how it has been put together : a short history of the formation of the earth, with its vegetable and animal life, from the earliest times, including an account of Pre-historic man, his Weapons, Tools, and Works online

called. But when I tell you that I have felt
the Earth tremble, and seen fire rushing out
from the top of a high mountain whose sides
were covered with snow, you will understand
how real it is though it may seem so strange.

People at one time liked to fancy that
powerful spirits lived in volcanoes and made
them their workshops : but we know better
now.

Well, the interior of the Earth is evidently
very different from the part we live upon ;
and it is the outside we have to think about
now, which would be dreadfully cold if the
sun did not shine upon it, though the inside
is so hot.

I have called this " the Geological Part,"
and the name Geological comes from two
Greek words meaning "a talk about the earth; "
but now you know it in its English dress it

C 2



20 THE GEOLOGICAL PART.

will be easy to recollect it. Geology is then the
study of the many kinds of rocks and fossils
which make up our World, but we must know
something of the way in which they are placed.

You may have noticed, if you have made
many journeys to different parts of England
or Wales, that the rocks or soils are very
different in various places. Sometimes we
find numerous chalk-pits, as in parts of Kent,
or Sussex ; if we go into Devonshire we may
notice the very red colour of the soil and of the
cliffs, especially near Sidmouth, Dawlish, and
Teignmouth ; in North Wales we find great
quarries and hills of slate ; while around
London we see a great deal of clay used for
making bricks, and called the London clay,
as well as many pits in gravel so useful for
making paths and mending roads, and in Kent
and Sussex chalk cliffs and hills are common.

Now after studying these various rocks
all over our country, we find that there is a
certain regular order in which they are found ;
some have been made a long time before
others, and while most kinds contain some
fossils, those found in the oldest rocks are



HOW THE ROCKS ARE PLACED. 21

much less like the living plants and animals
than the fossils we find in the newer rocks.

But you will want to know how it is that
we can tell that one rock is older than
another, when both appear at the surface of
the earth. It would take a long time to
make sure of this for ourselves, but it will be
enough to say that the various cliffs, quarries,
and railway-cuttings often show one kind of
rock resting upon another, and these always
occur in a certain order. Thus we never find
the Chalk resting on the London Clay, but we
constantly find the London Clay resting on
the Chalk. And this is proved in another
way, by deep well-borings. Underneath
London many wells have been carried down
right through the London Clay, and if only
continued deep enough they always reach
the Chalk. In the same way, the order of
the other rocks has been ascertained in
different parts of the country, by examining
all the pits and quarries, and cliffs and cut-
tings, with the help of what knowledge can
be obtained from deep mines and wells.

You will now begin to wonder why the



THE GEOLOGICAL PART.



older rocks should appear at the surface. I
have told you about earthquakes, and you
will find that many dreadful earthquakes
must in former times have ravaged our
country. The reason why the old rocks
come to the surface is because they have
been lifted up sometimes violently, but more
often very slowly. And the newer rocks
which formerly rested on them have very
often been quite washed away, either by the
sea or by rivers and little streams which for-
merly acted upon them.

Suppose then we take six books, some
thick and some thin, and pile them up to-
gether on the table, the lowest being a good
thick one. The lowest we will call granite,
the next slate, the third sandstone, the fourth
coal, the fifth chalk, and the sixth the London
clay. These will represent some of the
principal kinds of earths, and you can fancy
many more with other names coming between
them ; but the London clay can never be
below the granite nor the chalk below the
coal, for the great coal beds were formed long
before the chalk and clay. They generally



THE RAISING OF THE ROCKS. 23

come in much the same order as we have
named them, hard rocks like granite at the
bottom, and softer earths, like sandstone, chalk
and clay, a long way above them. But we do
not always find all these earths in one place
even if we dig ever so deeply, though the
granite would always be found at the bottom
if we went deep enough.

Sometimes the granite and other old rocks
have been pushed through the upper layers
by some great force, and have broken
them and risen above them in magnificent
mountain chains, like those of the Andes in
South, and the Rocky Mountains in North
America, the Wicklow Mountains in Ireland,
the Grampians in Scotland, and the Cornish
mountains in England. We can easily sup-
pose that the lowest of our books (the granite
book) has been pushed upwards by some
great force from below, and parts of it broken
through the others, and raised high above
them; and this is what has actually been
done with real rocks. And as this kind of
upheaval has taken place at different periods
of the earth's history, we find that granites
have come to the surface at different times.



24 THE GEOLOGICAL PART.

When the layers are thus broken through
they are often tilted up on end and tumbled
about in confusion. But where there has
been no disturbance like this, they generally
rest evenly upon one another in their proper
order.

Granite, and rocks of the same kind, are
not in the least like chalk, or clay, or even
sandstone, and when once you have seen any
of these you will not be likely to mistake it
for the others. Granite is excessively hard,
and has a beautiful appearance when polished,
with a number of brilliant white and some
dark specks in it. It is used for paving the
streets of towns, for which purpose it is cut
into oblong blocks, and for the pillars of fine
buildings. Sometimes it is dark brown,
sometimes reddish, but generally a bluish
grey. This rock is composed of a great
quantity of crystals, and for this reason it is
thought it must have been melted at one
time by intense heat in the earth, and after-
wards slowly cooled. Chalk is very different,
and sandstone, though it is also hard, not in
the least like granite.



HOW THE ROCKS WERE FORMED. 25



HOW THE ROCKS WERE FORMED.

What I have just said is about all that we
know of the formation of the oldest and hard-
est granite rocks : but there is something going
on now which confirms the belief that the
materials of which they are made were melted
together by a greater heat than we can make
in our furnaces for melting iron ; for I should
tell you that it is easier to melt iron and
copper than granite rocks. Volcanoes often
throw out melted earths which when cooled
appear to be made of much the same mate-
rials as these granites.

SANDSTONE.

But we know more of the manner of the
formation of sandstone. This rock is com-
posed of rounded grains of sand just like that
we find upon the sea shore. If you take a
handful of this sand and squeeze it tightly,
it will keep together a little while. Now
suppose a quantity of this sand was pressed
by a very great weight the weight of a



26 THE GEOLOGICAL PART.

large hill for instance after many years the
grains would stick firmly together, and be-
come a sort of stone. It is in this way the
sandstones must have been formed, and per-
haps heat helped the work, though not so
great a heat as melted the granite. The
sand, after it had been washed upon the sea
shore, became gradually covered with other
earths hundreds of feet thick, and the im-
mense weight above it pressed it into stone :
but you may imagine how very long a time
it took to do this. Sandstones are used for
building, but they do not last very long ; the
frost makes little cracks in them and they
soon crumble away to the grains of sand of
which they were made. Several fossils are
found in some of these sandstones, which
have been formed at many different periods
of the earth's history.



CHALK.

You have seen those high cliffs of chalk
along the south coast of England, perhaps,
and you have wondered what that beautiful



THE CHALK BEDS. 27

white earth was, and how it came there. It
is found in many parts of the world, and
the south and south-east of England are to a
great extent composed of it. The material
is called by chemists carbonate of lime. It
is almost entirely made up of minute shells
called foraminifera, from two Latin words
which mean that there are many openings or
chambers in their shells, and there are many
beautiful fossils called ammonites imbedded in
the chalk. These are shell-fish, two or three
inches, and sometimes a foot across, and their
shape is very like that of the young leaves of
the common fern before it has opened in the
spring.

Millions of these tiny foraminifera are
living now in parts of the Atlantic and Pacific
oceans, and when they die their shells sink
to the bottom and form a greyish mud, some-
thing like chalk.

When H.M.S. " Challenger " was sent out
in the year 1873, to find out what was at the
bottom of the deepest seas of the World,
great interest was felt in the expedition,
because we were sure that we should learn



28 THE GEOLOGICAL PART.

something about the manner in which some
of the rocks were formed.

We knew that the whole of the beds of
the present seas must be receiving the wash-
ings of the rivers and the bodies of many
fishes and animals, and that the rocks of the
future must be forming down there by these
accumulations. Long lines were let down from
the ship with a dredge at the end, and thus
parts of the bottom of the sea were brought
up and carefully examined. It was found
that the washings, stones, clay, and mud of
the land were carried hundreds of miles out
to sea, and laid upon the bottom. But in the
deeper parts, where the Alps would be almost
covered there was a fine grey mud com-
posed almost entirely of the shells of the
little foraminifera, and this, no doubt, is the
chalk of future times, or perhaps limestone
of a harder kind. Deeper, too, than where
this grey mud is found, there is a reddish
mud, exceedingly fine and soft. We cannot
exactly say yet whether this is formed from
the remains of shell-fish ; but it is, at all
events, very like the clay of the land, and in



CHALK UNDER THE OCEAN. 29

some future time will most likely become like
that stiff mud we know so well. So that
even the materials for bricks are being made
now, and perhaps when all those hundreds
of islands scattered about the Pacific Ocean
are joined into one great Continent, this red
mud will be raised and made use of for build-
ing the houses of new peoples and nations.

When we see this going on now, of course
it is very easy to conclude that the chalk, a
great deal of which is above the sea now,
must have been formed in the same way at the
bottom of an ancient ocean, and afterwards
raised by the same kind of upward force which
made the granite break through other earths.

If we did not know that the same cause was
at work now, and that the same kinds of shell-
fish were living and laying down new beds of
chalk under the sea, we should not know
how to account for the quantities of chalk in
the world. For innumerable agest hese little
creatures have thus been paving the floor of
the ocean with their dead bodies, and you
may suppose that countless millions of them
must have lived and died ! In some of the



30 THE GEOLOGICAL PART.

chalks the shells of the foraminifera can be
quite distinctly seen with a microscope, and
when these are compared with the shells of
living ones, they are seen to be almost exactly
alike. Next time you pass through one of the
railway cuttings through the chalk in going to
Brighton, or Ramsgate, or Dover, remember
that those high cliffs were built up by these
Liliputian giants under the sea, and you may
think of the chalk as " foraminifera earth."



COAL.

You see this black shining substance
almost every day, and you know it is dug up
from very deep pits where the poor miners are
often killed by explosions of gas escaping
from it. But it is as well to know what
it is and how it comes to be so useful to us.
In the language of chemistry it is called
" carbon," and a great writer has given it the
poetical name of " compressed sunlight." But
you will ask how sunlight could possibly
get into a deep mine, and how it could be
compressed there. You will see that the



THE COAL BEDS. 31

explanation is really quite simple by-and-by.
This coal was once above ground, and was
a splendid forest of waving palm-trees, and
ferns, and gigantic mosses, as you will see by
the pictures of the fossils of them.

Many of the animals and plants of past
times were giants compared to those living
now, of the same species or kind, and many
of the plants of the present time are dwarfs
to those of the same kind which formed the
coal beds. Many generations of trees must
have grown and died, and others must have
sprung up, and so on, until beds of them,
some ten, others twenty, or even thirty feet
thick, were formed. Here, buried in the
coal, are the stems, leaves, bark, roots, fruit,
and seeds of these trees, and we can have no
doubt that almost the whole of the coal is
composed of them. You must not expect to
find the shapes of these in every piece of coal
you may happen to look at, because most of
it has been greatly changed by the great
weight and pressure upon it, and the length
of time : but it is certainly all the same sub-
stance wood turned into coal. The fossil



32 THE GEOLOGICAL PART.

plants of the coal are of course entirely
black, but there is no mistake about their
having once been living plants.

You will ask perhaps how the coal came
to be buried so deep. It is not so always,
being sometimes at the surface. But just as
the granite has been pushed up through the
other rocks, so has the coal in some places
been uplifted and in others has sunk down.
It was often covered up by other earths to
a great depth, after the trees which com-
posed it had died ; but where it is now at
the surface these newer earths have been
afterwards worn away. When the sun shone
upon these coal trees they took its warmth
and light into their stems and leaves, for they
could not live without, and this made them
grow so fast and become so large that it is
not untrue to call coal " compressed sunlight."
Charcoal is in some respects so like coal that
it would seem to you at once that they were
probably the same material. Charcoal is
simply burnt wood, and when the coal forests
had died down, and when these beds sank
down beneath other layers the pressure and



CLAY, MUD, AND GRAVEL. 33

heat together turned the wood and leaves
into a hard mass like charcoal in colour, but
heavier and more solid, and just enough of the
stems and leaves have been left to enable
us to know with certainty that coal was once
wood.

We light our fires now and drive our
steam-engines with the heat of the sun which
shone upon the coal forests, and has been
stored up for many thousands of years in the
Earth, to be brought out once more to give
us light and warmth.

CLAY AND MUD.

While the ancient forests were growing
up to form the coal beds, and the foramini-
fera were slowly building up the chalk, as I
have explained, the Earth was covered with
water in some places which are now dry land,
and the sea now flows over parts of the
World which were once the habitations of
plants and animals. These great changes
have left their marks upon many a mountain
side, and many an old river or sea bed has
become filled up. A map of Europe during
D



34 THE GEOLOGICAL PART.

the chalk period would show that the places
where Paris, London, Copenhagen, and Berlin
now are were then under the ocean ; but
since then these places have been lifted up,
and mud, clay, and gravel swept over the
chalk in many places by the action of new
rivers and seas. Water, you perceive, has
had a great deal to do with these changes,
and indeed it is one of Nature's most power-
ful tools, for it can wash down rocks and
cliffs and cut its way in rivers for thousands
of miles over the Earth's surface. It carries
down mud, and clay, and gravel, and this
soil, which has been named alluvium, is one
of the most interesting of all to us, because it
contains the bones of the immense animals we
shall talk about presently, as well as those of
the oldest races of men with their weapons
and ornaments.

The mud age, and we are in the mud
and gravel age now, belongs to what is called
the Tertiary period, and we shall see that
this age has lasted a very long time already,
so long that though it is still going on, the
most extraordinary animals have lived and



CLAY, MUD, AND GRAVEL. 35



died, and not one of them is now left alive.
Still the same washing and cutting of water is
going on which buried their bones in swamps,
and bogs, and river caves, and may perhaps
carry away some of the bones of us who are
living now, to be found ages afterwards by
future generations who will read our history
in these silent witnesses, as we read the history
of the tree fern sand foraminifera in the coal
and the chalk.

The present age of the World's history
is the Mud age, or, as we shall call it in future,
the Tertiary period, and I think you will agree
with me when I come to describe it, that it
contains the most interesting of all the pieces
of " the puzzle of life."

The earth of the Tertiary period is very
different from a great many of the older
earths. Clay, mud, and gravel are the wash-
ings only of the older rocks, the fine par-
ticles which have been worn off from them
by frost and water and carried down by
rivers and left in large beds, and sometimes
they have a good deal of decayed wood and
weeds mixed with them. Here are found

D2



36 THE GEOLOGICAL PART.

the bones of the great animals which were so
much larger and stronger than those of the
same kind living now, or any that lived
before them.

UPHEAVAL AND DEPRESSION.

These two words are so often used in
books on geology that we shall not be able
to get on without knowing their meaning. We
have seen that the rocks have been formed
in a certain way some by heat, some by
water, and some by dead forests and
that they lie over one another in pretty
regular order. But this order has sometimes
been disturbed and the layers have been
tumbled about among one another very
much. In some places the older rocks, such
as granite, slate, and sandstone, have been
pushed up through those above, and in
others the coal has sunk down and been
covered with thick layers of chalk, sand, and
mud. When the force below pushes a layer
up through the others it is called upheaval,
and when a layer sinks down it is called
depression, or subsidence. Both these actions



UPHEAVAL AND DEPRESSION. 37

are going on now in different parts of the
Earth. A great part of Sweden, Norway,
and Denmark, of Spitsbergen, Siberia, and
the north of America, is being slowly raised
higher above the sea, as we know by the
height their old sea beaches now are above
the water ; while part of the shore of
America opposite to Europe and also the
south of Greenland is slowly sinking down,
as we know by the remains of land animals
and trees which are now covered by the
tide ; and at many places on the coast
of India this subsidence is also going on.
Nearer home, too, there is an example
of it in the island of Guernsey. All round
the coast of this island, like that of Jersey, are
found tree trunks and other remains of old
forest land beneath the water. Old histo-
ries refer to this as dry land ; and if a map
of it made in 1406 is correct, this land must
have sunk about 1 50 feet since that time.

Thus we can see, even at the present
time, the very same changes which have
worked upon our Earth for innumerable
ages. It is now easy to understand how the



38 THE GEOLOGICAL PART.

forests which must have grown above in the
air have, after a long time, sunk down to a
great depth, and been turned into coal, and
covered with the sediment, sand, gravel,
and chalk from the seas which afterwards
flowed over the places where they grew.

Sometimes the rocks by the sea shore are
cut into terraces or steps by the constant
wear of the water, and when we see these
water marks far above the present level of the
sea we know that the land must have been
lifted up gradually above the sea. There are
many such terraces in Norway. To prove
whether this is so marks have been cut upon
rocks at a measured height above the sea,
and after some years these marks have been
noticed to have been raised much above
the water by the " upheaval " of the earth at
that place.

Generally this change of level has taken
place gradually, and the greatest work in
moving the layers of earth and displacing
them has been very slow. But in some places
violent and sudden shocks have happened,
tearing up the rocks and piling them up in



ISLANDS APPEAR AND DISAPPEAR. 39

heaps ; and now and then islands have sud-
denly appeared in the sea and vanished out
of sight completely in a short time. Islands
have thus come up in the Mediterranean Sea
within the memory of man. In the year 1831
the island of Julia suddenly appeared near the
coast of Sicily, and since the year 186 B.C. no
less than three islands have started up in the
bay of the island of Santorin. In this century
islands have appeared among the Azores, the
Indian Archipelago, the Philippines, the
Moluccas, and on the coast of Kamtschatka
and other places. Some of these have ap-
peared suddenly, others slowly, and they no
doubt have been raised by a great force from
below.

You will see now how easy it is to account
for the changes of the places of the layers of
rock. The same thing is going on now which
has been going on throughout all time, only
perhaps with more energy formerly than now,
making mountains, islands, and continents,
raising up a large tract of land in one place
and sinking an island or a sea shore in
another.



40 THE GEOLOGICAL PART.

These changes have been of great use to
us too. Suppose all England had been covered
with coal or slate, we should not have been
able to grow anything! As it is we have
sand and gravel in one county, chalk in
another, slate or granite in another, and coal
down below in several, and we can grow a
great variety of plants on all these different
soils. We have to thank " upheaval " and
" depression " for this. The force which is
always working below us has turned up the
different soils like a gigantic plough, and
brought some to the top and covered others,
so that instead of having to dig down deeper
than ever we have yet, we have only to go
from one county to another to find the
different rocks. We know that we could not
get at the coal in Sussex without going down
an unknown depth through the chalk and
other earths, but we dig for it in the North
of England, where we know its depth below
the surface.

I will try now to give you some idea of
the way in which the rocks come in their
order, or the succession of formations as



THE SUCCESSION OF FORMATIONS. 41

geologists call it. If we started to walk from
Wales to London the rocks we should pass
over would be slate and flagstones in
Wales, and going en towards London, lime-
stone, old red sandstone, more limestones,
coal beds, new red sandstone, oolite, green-
sand, chalk, and last London clay. We
might not always find each of these near the
surface, but they would be found to be the
principal rocks on a line between Wales and
London, the oldest being in Wales and the
newest or most recent as we get nearer
London. That word " oolite " which I used
comes from two Greek words meaning " roe "
and " stone," because the rock is composed of
little rounded grains of a chalky substance
shaped like the hard roe of a fish, or like
sago before it is cooked.

If you look at the following table you will
see how the principal rocks are placed one
upon the other, beginning at the lowest or
oldest at the bottom and going up to the
newest at the top of the table, and on the
right hand side I have written the names of
the principal fossils which each kind of earth
contains.



THE GEOLOGICAL PART.



TABLE OF THE SUCCESSION OF FORMATIONS.






("Peat-bogs and caves
River-mud and brick-
earth, gravels, and
boulder clay (allu-
vium)

Crag of Eastern Coun-
ties
i London clay, &c.

/ Chalk (with and with-