pters we now expect to find a warmer climate, and the
record gives abundant proof of it. To this period belongs the "London
Clay," in whose thick and--to the unskilled eye--insignificant bed the
geologist reads the remarkable story of what London was two or three
million years ago. It tells us that a sea, some 500 or 600 feet deep,
then lay over that part of England, and fragments of the life of the
period are preserved in its deposit. The sea lay at the mouth of
a sub-tropical river on whose banks grew palms, figs, ginkgoes,
eucalyptuses, almonds, and magnolias, with the more familiar oaks and
pines and laurels. Sword-fishes and monstrous sharks lived in the sea.
Large turtles and crocodiles and enormous "sea-serpents" lingered
in this last spell of warmth that Central Europe would experience.
A primitive whale appeared in the seas, and strange large
tapir-like mammals--remote ancestors of our horses and more familiar
beasts--wandered heavily on the land. Gigantic primitive birds,
sometimes ten feet high, waded by the shore. Deposits of the period at
Bournemouth and in the Isle of Wight tell the same story of a land
that bore figs, vines, palms, araucarias, and aralias, and waters that
sheltered turtles and crocodiles. The Parisian region presented the same
features.

In fact, one of the most characteristic traces of the southern sea which
then stretched from England to Africa in the south and India in the
east indicates a warm climate. It will be remembered that the Cretaceous
ocean over Southern Europe had swarmed with the animalcules whose dead
skeletons largely compose our chalk-beds. In the new southern ocean
another branch of these Thalamophores, the Nummulites, spreads with such
portentous abundance that its shells--sometimes alone, generally with
other material--make beds of solid limestone several thousand feet in
thickness. The pyramids are built of this nummulitic limestone. The
one-celled animal in its shell is, however, no longer a microscopic
grain. It sometimes forms wonderful shells, an inch or more in diameter,
in which as many as a thousand chambers succeed each other, in spiral
order, from the centre. The beds containing it are found from the
Pyrenees to Japan.

That this vast warm ocean, stretching southward over a large part
of what is now the Sahara, should give a semitropical aspect even to
Central Europe and Asia is not surprising. But this genial climate was
still very general over the earth.