"
The children had been with me to the Museum in the town in which we lived,
and had looked with wonder at the huge creatures whose skeletons have
been built up bone by bone, after being taken from their rocky tomb--for
this earth of ours which has seen so many changes has been rifled of her
treasures; not the gold and silver, coal and iron with which she is so
richly stored, but the wonderful specimens of God's work in bygone ages
which He has allowed us to see; so that we cannot doubt that such creatures
once existed, though we may know nothing with certainty as to the time of
their first appearance in the sea and on the dry land, and can only guess
at the kind of life they lived.
You remember that we spoke, in the chapter about the earth's crust, of the
"fire-made rocks," which were once in a liquid state from intense heat
(we could not expect to find any remains of plants or animals there, and
none _have_ been found), and of the "water-made rocks," which have been
gradually accumulated by the action of water in wearing down the land.
These rocks lie in layers, and fossil shells, plants, and bones of animals
have been found in them, as we have already seen.
But how did these fossils get into the rocks? And how is it that they have
been found in all countries and at all heights above the sea?
Before I try to answer these questions, I must tell you that when
geologists speak of "rock" they mean everything which has gone to form the
crust of the earth, whether clay, or loose sand and gravel, or the hard
heavy granite which some of us had seen crowning the Dartmoor tors.
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