the temperature of the Atlantic. In Europe there is a similar
chill, and a more obvious reason for it. There is an ascending movement
of the whole series of mountains from Morocco and the Pyrenees, through
the Alps, the Caucasus, and the Carpathians, to India and China. Large
lakes still lie over Western Europe, but nearly the whole of it emerges
from the ocean. The Mediterranean still sends an arm up France, and with
another arm encircles the Alpine mass; but the upheaval continues, and
the great nummulitic sea is reduced to a series of extensive lakes, cut
off both from the Atlantic and Pacific. The climate of Southern Europe
is probably still as genial as that of the Canaries to-day. Palms still
linger in the landscape in reduced numbers.

The last part of the Tertiary, the Pliocene, opens with a slight return
of the sea. The upheaval is once more suspended, and the waters
are eating into the land. There is some foundering of land at the
south-western tip of Europe; the "Straits of Gibraltar" begin to connect
the Mediterranean with the Atlantic, and the Balearic Islands, Corsica,
and Sardinia remain as the mountain summits of a submerged land. Then
the upheaval is resumed, in nearly every part of the earth.

Nearly every great mountain chain that the geologist has studied
shared in this remarkable movement at the end of the Tertiary Era. The
Pyrenees, Alps, Himalaya, etc., made their last ascent, and attained
their present elevation. And as the land rose, the aspect of Europe
and America slowly altered. The palms, figs, bamboos, and magnolias
disappeared; the turtles, crocodiles, flamingoes, and hippopotamuses
retreated toward the equator. The snow began to gather thick on the
rising heights; then the glaciers began to glitter on their flanks. As
the cold increased, the rivers of ice which flowed down the hills
of Switzerland, Spain, Scotland, or Scandinavia advanced farther and
farther over the plains. The regions of green vegetation shrank before
the oncoming ice, the animals retreated south, or developed Arctic
features. Europe and America were ushering in the great Ice-Age, which
was to bury five or six million square miles of their territory under a
thick mantle of ice.

Such is the general outline of the story of the Tertiary Era. We
approach the study of its types of life and their remarkable development
more intelligently when we have first given careful attention to this
extraordinary series of physical c