hern Siberia either perished or migrated
southward. From there they gradually penetrated into European Russia. He
believed that before the Glacial period a connection existed between the
Aralo-Caspian Sea and the Arctic Ocean, carrying warm water northward.
The gradual disappearance of this marine channel caused a decrease of
warmth in Northern Asia, so that large accumulations of frozen soil and
ice were formed, which still more depressed the temperature. This, he
suggested, probably took place at the time when the Glacial period
commenced in North-western Europe.

It has been urged against these views of Tcherski and Brandt, that the
bone beds in the Liakov Islands (New Siberian Islands) rest partly upon
a solid layer of ice of nearly seventy feet thick. This mass of ice, it
was thought, must have accumulated during the Glacial period. As the
bones rest upon it, the mammals could only have lived in those islands
in more recent times, after the Ice-Age had passed away. Nothing,
apparently, can be clearer, and yet in the face of this seeming proof
one feels, as I have mentioned before, that if such an extraordinary
revolution of climate as is implied by this admission had taken place,
we should be able to perceive the traces throughout the northern
hemisphere. In this dilemma, a suggestion made by Dr. Bunge, who visited
the New Siberian Islands recently at the instance of the Imperial
Academy of St. Petersburg, helps us out of the difficulty. He found
that, as a rule, these so-called fossil glaciers contain seams of mud
and sand, and he argued that the ice had formed, and is still forming at
the present day, in fissures of the earth. I entirely concur with this
view. Neither palaeontology nor the geographical distribution of animals
lend any support to the other theory, and I think we may conclude that
Brandt's view in the main is probably the correct explanation of the
phenomena which we have discussed. Some important facts of distribution
are more easily explicable on this assumption. Why, for instance, should
the Siberian fauna of pliocene times have remained in Siberia and not
have migrated to Europe at that time? The pliocene mammals of Siberia
are mostly of southern origin. Their range increased enormously during
the epoch throughout Northern Asia. We should expect them, therefore, to
have crossed the Caspian plains, or even the low-lying Ural Mountains,
to pour into the neighbouring continent. But Professor Brandt