currents, and
probably destroyed a vast tract of land between England and France,
and probably also, that sunken island of Atlantis of which old Plato
dreamed--the vast tract which connected for ages Ireland, Cornwall,
Brittany, and Portugal. That convulsion covered up the rich clays
with those barren sands and gravels, which now rise in flat and
dreary steppes, on the Beacon Hill, Aldershot Moors, Hartford Bridge
Flat, Frimley ridges, and Windsor Forest. That rich old world was
all swept away, and instead of it desolation and barrenness, piling
up slowly on its ruins a desert of sand and shingle, rising inch by
inch out of a lifeless sea. There is something very awful to me in
the barrenness of those Bagshot sands, after the rich tropic life of
the London clay. Not a fossil is to be found in them for miles.
Save a few shells, I believe, near Pirbright, there is not a hint
that a living being inhabited that doleful sea.

But do not suppose, gentlemen and ladies, that we have yet got our
gravel-pit made, or that the way-worn pebbles of which it is
composed are near the end of their weary journey. Poor old stones!
Driven out of their native chalk, rolled for ages on a sea-beach,
they have tried to get a few centuries' sleep in the Eocene sands on
the top of the chalk hills behind us, while the London clay was
being deposited peacefully in the tropic sea below; and behold, they
are swept out, once more, and hurled pell-mell upon the clay, two
hundred feet over our heads.

Over our heads, remember. We have come now to a time when Hartford
Bridge Flats stretched away to the Beacon Hill, and many a mile to
the south-eastward--even down into Kent, and stretched also over
Winchfield and Dogmersfield hither.

What broke them up? What furrowed out their steep side-valleys?
What formed the magnificent escarpment of the Beacon Hill, or the
lesser one of Finchamstead Ridges? What swept away all but a thin
cap of them on the upper part of Dogmersfield Park, another under
Winchfield House; another at Bearwood, and so forth?

The convulsions of a third world; more fertile in animal life than
those which preceded it: but also, more terrible and rapid, if
possible, in its changes.

Of this third world, the one which (so to speak) immediately
preceded our own, we know little yet. Its changes are so
complicated that geologists have as yet hardly arranged them. But
what we can see, I will sketch for you shortly.

A great