Page:Early Man in Britain and His Place in the Tertiary Period.djvu/63

] possess characters bringing them into relation with one or other of the families of hoofed quadrupeds living in the Eocene period (see Fig. 5).

The climate of Britain is proved to have been tropical from the time of the London Clay down to the close of the Eocene period by the concurrent testimony of the flora and of the fauna. Just as a high temperature is necessary for the well-being of the feather-palms (see Fig. 4) and large fan-palms, so is it necessary for the full development of the larger forms of reptilian life, such as the alligator, crocodile, and gavial. Among living mammals, the tapir, the inhabitant of the warmer regions of Asia and America, is the closest representative of a large section of the Eocene mammalia, and the lemurs of the present day are only found in hot climates. The nautilus, larger volutes, cowries, and other shells, so common in the Eocene strata, are now only to be met with in the tropical and sub-tropical seas. Mr. Starkie Gardner estimates the mean annual temperature of Britain in the mid Eocene age at 70°, from the examination of the fossil plants.

It is impossible for the reader who has followed these three stages of the Eocene period not to be impressed with the extraordinary character of the mammalia. They stand in the same relation to living species that the main