the Glacial Age proper.

The best authorities also suppose that the reign of snow and ice
was broken by at least one return (possibly more) of genial
climate, when animals and plants from the south again visited
the countries of Northern Europe--only, however, to be once more
driven forth by a return of arctic cold. But finally, before the
increasing warmth of a genial Climate, the glaciers vanished,
not to return again, and the Glacial Age became merged in that
of the present.

It is no longer a question that man lived in Europe during the
largest portion of this age, if not from the beginning. It is
necessary, then, to come to a clear understanding of the
successive stages of this entire age, and to trace the wonderful
cycles of climate--the strange mutation of heat and cold, which
must have exerted a powerful influence on the life, both animal
and vegetable, of the period--and see when we first find
decisive proofs of man's presence, and learn what we can of
his condition.

The map of Europe, at the close of Pliocene times and the
commencement of the Glacial Age, is of interest to us in several
ways. From this it will be seen that it was considerably more
elevated than at the present. As this is no fancy sketch, but is
based on facts, it is well to outline them. Without the aid of
man, land animals can not possibly pass from the mainland of a
continent to an island lying some distance off the shore. But it
is well known that animals like the rhinoceros, and several
others, wandered as well over the surface of the British Islands