reland at the present day, where, as we all know, anything
but a dry steppe-climate prevails.

Dr. Kobelt quite agrees with me in thinking that the remains of the
mollusca found along with the so-called "steppe-mammals" afford no proof
of a steppe-character of the country at the time when they were alive
(p. 166). Nor do the mollusca which have been found in England in the
Forest-Bed and the succeeding pleistocene strata support such a view.
The Forest-Bed, generally regarded as belonging to the Upper Pliocene, I
believe to be an inter-glacial pleistocene deposit--contemporaneous with
the loess formation in Germany. Of fifty-nine species of land and
freshwater mollusca which have been discovered in this bed, forty-eight
species, according to Mr. Clement Reid (p. 186), are at present living
in Norfolk, six are extinct, two are continental forms living in the
same latitudes as Norfolk, and the other three are all southern forms.
Not a single species has a particularly northern range. Of the land and
freshwater mollusca of the South of England in the succeeding
pleistocene deposits, six species are now no longer living in the
British Islands, but only one (_Helix ruderata_) can be looked upon as
an Arctic or Alpine form. After this short digression on the mollusca, I
will briefly recapitulate what is known about the early history of the
Siberian mammals, which will assist us in tracing the cause of their
migration to Europe.

We have in Siberia problems quite as difficult of solution as the
European ones. Volumes have been written to explain the former presence
of Arctic mammals like the Reindeer in Southern Europe, and the most
extraordinary demands on the credulity of the public have been made by
some geologists in their attempts to account for this comparatively
simple problem. In Northern Asia a somewhat similar phenomenon, but much
more difficult of explanation, has taken place. Mammals have been found
fossil in recent geological deposits in localities where they do not now
occur, and apparently the Siberian and the European deposits are of
about the same age. Now, however, comes the extraordinary difference. In
Europe the Arctic mammals went southward, but in Siberia the Southern
ones went northward. Not only do we find the Saiga-Antelope, Tiger,
Wild Horse, European Bison, Mammoth, and Rhinoceros in the extreme north
of the mainland of Siberia; their remains have even been obtained in the
New Siberian Islands. As t