Now, this great bed of London clay, even more than the sands below
it, deserves the title of a new creation.
As a proof--some of you may recollect, when the South-Western
Railway was in making, seeing shells--some of them large and
handsome ones--Nautili, taken out of the London clay cutting near
Winchfield.
Nautili similar to them (but not the same) are now only found in the
hottest parts of the Indian seas; and what is more, not one of those
shells is the same as the shells you find in the chalk. Throughout
this great bed of London clay, the shells, the remains of plants and
animals, are altogether a new creation. If you look carefully at
the London clay shells, you will be struck with their general
likeness to fresh East Indian shells; and rightly so. They do
approach our modern live shells in form, far more than any which
preceded them; and indeed, a few of the London clay shells exist
still in foreign seas; in the beds, again, above the clay, you will
meet with still more species which are yet alive; while in the
chalk, and below the chalk, you never meet, I believe, with a single
recent shell. It is for this reason that the London clay is said to
be Eocene, that is, the dawn of the new creation.
The chalk, I told you, seems to have been deposited at the bottom of
a still and deep ocean. But the London clay, we shall find, was
deposited in a comparatively shallow sea, least in depth toward High
Clere on the west, and deepening towards London and the mouth of the
Thames.
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