ropical hippopotamus, it
managed to survive the long and cold winters which suited the arctic
species.

Moreover, no such calculations can really be made with accuracy: we do
not know what other astronomical facts may have to be taken into
consideration, nor can we say when such "periods" as those which are so
graphically described, began or ended.

In this very instance, we know that the mammoth only became extinct in
comparatively recent times, since specimens have been found in Siberia,
with the hair, skin, and even flesh, entirely preserved. Granted that
the intense cold of the Siberian ice effected this, it is impossible to
admit more than a limited time for the preservation--not hundreds of
thousands of years. Professor Boyd Dawkins is surely right in stating
that the calculations of astronomy afford us no certain aid at present
in this inquiry.

As regards the geological indications of age, the best authority seems
to point to the first appearance of man in the post-glacial times: that
is to say, that the gravels in which the palaeolithic implements are
found were deposited by the action of fresh water after the great
glacial period, when, at any rate, Northern Europe, a great part of
Russia, all Scandinavia, and part of North America were covered with
icefields, the great glaciers of which left their mark in the numerous
scoopings out of ravines and lake beds and in the raising of banks and
mounds, the deposit of boulders, and the striation of rocks _in situ_,
which so many districts exhibit.

The few instances in which attempts have been made, in Italy or
elsewhere, to argue for a pliocene man (i.e. in the uppermost group of
the tertiary) have ended in failure, at least in the minds of most
naturalists competent to judge.

One of the most typical instances of the position of the implement age
has been discovered by Fraas at Shuessenried in Suabia; here the remains
of tools and the bones of animals (probably killed for food) were found
in holes made in the glacial _debris_.

But here, again, it is impossible to say when this glacial age
terminated, and whether man might not have been living in other more
favoured parts while it was wholly or partially continuing.

In Scandinavia no palaeolithic stone implements have been found, from
which it may be inferred that the glacial period continued there during
the ages when palaeolithic man hunted and dwelt in caves in the other
countries where his remains occ