grew warmer again.

Now what proof is there of that?

This. Underneath London--as, I dare say, many of you know--there
lies four or five hundred feet of clay. But not ice-clay. Anything
but that, as you will see. It belongs to a formation late
(geologically speaking), but somewhat older than those Disco Island
beds.

And what sort of fossils do we find in it?

In the first place, the shells, which are abundant, are tropical--
Nautili, Cones, and such like. And more, fruits and seeds are found
in it, especially at the Isle of Sheppey. And what are they? Fruits
of Nipa palms, a form only found now at river-mouths in Eastern India
and the Indian islands; Anona-seeds; gourd-seeds; Acacia fruits--all
tropical again; and Proteaceous plants too--of an Australian type.
Surely your common sense would hint to you, that this London clay
must be mud laid down off the mouth of a tropical river. But your
common sense would be all but certain of that, when you found, as you
would find, the teeth and bones of crocodiles and turtles, who come
to land, remember, to lay their eggs; the bones, too, of large
mammals, allied to the tapir of India and South America, and the
water-hog of the Cape. If all this does not mean that there was once
a tropic climate and a tropic river running into some sea or other
where London now stands, I must give up common sense and reason as
deceitful and useless faculties; and believe nothing, not even the
evidence of my own senses.

And now, have I, or have I not, fulfilled the promise which I made--
rashly, I dare say some of you thought--in my first paper? Have I,
or have I not, made you prove to yourself, by your own common sense,
that the lowlands of Britain were underneath the sea in the days in
which these pebbles and boulders were laid down over your plains?
Nay, have we not proved more? Have we not found that that old sea
was an icy sea? Have we not wandered on, step by step, into a whole
true fairyland of wonders? to a time when all England, Scotland, and
Ireland were as Greenland is now? when mud streams have rushed down
from under glaciers on to a cold sea-bottom, when "ice, mast high,
came floating by, as green as emerald?" when Snowdon was sunk for at
least fourteen hundred feet of its height? when (as I could prove to
you, had I time) the peaks of the highest Cumberland and Scotch
mountains alone stood out, as islets in a frozen sea?

We want