s, and the pouched Marmots. It might be
urged that some of the smaller Siberian carnivores and rodents do
inhabit the Alps. So they do. The Stoat and Weasel have found such a
congenial home in Europe, both in the plain and mountains, that they
have spread rapidly to the latter, and no doubt reached within a
comparatively short time the great heights at which they now occur in
the Alps. But the Voles (_Arvicola_) have scarcely spread beyond the
region of fields and cultivated ground. A height of 5000 feet at the
most marks their maximum altitude in the Alps.

The fauna which reached the Alps in miocene and pliocene times, as well
as the indigenous element, must have survived the Glacial period in
their mountain home. Though I think that the conditions of the climate
at that time and the size of the Scandinavian glaciers have been greatly
exaggerated, there can be no doubt at all about the enormous size of
many of the Alpine glaciers at this period. The climate was probably
much moister but not colder than what it is now, possibly warmer. The
snowfall was therefore greater, so that glaciers filled many of the
lower valleys of Switzerland which are now quite free from ice, and even
invaded the plain. But there is no reason whatsoever why the Alps should
not even then have supported a luxuriant fauna and flora as they do now.
Possibly many of the miocene plants and animals became extinct then, but
extinction of species occurs at the present day. We hear complaints that
the Chamois and the Steinbock have nearly vanished; we know that the
Marmot is now much scarcer than it used to be, and that the Edelweiss
and many other plants are more and more difficult to find, and seem
rapidly to disappear. No doubt all this is in a great measure due to
the influence of man, but not altogether. There is a constant struggle
for existence going on among the animals and plants themselves--the
stronger and fitter species driving the less fit and weaker into a
corner, where they finally succumb. This happens now just as it did in
pliocene and pleistocene times, and need not imply change of climate.

As soon as the Miocene sea to the north of the mountains had retreated,
a portion of the Alpine fauna poured into the plain, and many species
have found their way to the British Islands, a few to Scandinavia and
Russia. Westward too, the sea soon after retired and opened a way for
those Alpine species which were vigorous enough to extend their ran