e or
less arctic climate; many of the Voles (_Microtus_), Picas (_Lagomys_),
and Susliks (_Spermophilus_), together with the Saiga Antelope, appear
to point equally strongly to the prevalence of a Steppe-like condition;
while the Hippopotamus and Spotted Hyaena seem as much in favour of a
sub-tropical state of things. Many attempts have been made to reconcile
these apparently contradictory circumstances; one of the older views
being that while the tropical types of animals lived during a warm
interlude, they migrated southwards with the incoming of colder
conditions to the arctic type of fauna. Since, however, it has now been
ascertained that the remains of both tropical and arctic forms have been
found lying side by side in the same bed, it is perfectly certain that
such an explanation will not meet the exigencies of the case" (p. 300).

In Germany the remains of the Siberian mammals occur to a large extent
in a pleistocene deposit known as "loess," and the theory has of late
years gained ground that the latter is the fine dust-like sand
accumulated during an intensely arctic dry climate. That many of the
mammals discovered in the "loess" now inhabit the dry steppes of Eastern
Europe and North-Western Asia seems to lend support to this supposition;
but besides the mammals there are also land and freshwater shells in
this deposit. The molluscan fauna certainly indicates no
steppe-character, according to Dr. Kobelt (_b_, i. p. 166).

The attempt to utilise the Siberian migrants to Europe as indicators of
a severe climate there, certainly fails to establish conviction. But it
may be asked, surely the remains of the Alpine and Arctic plants which
have been found in pleistocene deposits must decide this question in
favour of one or the other hypothesis? Let us test it.

Plants being more directly affected than animals by changes of
temperature and rainfall, remarks Mr. Clement Reid (p. 185), give
evidence of the highest value when we inquire into former climatic
conditions. The severity of the climate during the Glacial period is
often assumed from the occurrence in pleistocene strata of such plants
as _Dryas octopetala_, some species of willow, the dwarf birch, and
others, which are now found in high latitudes and in the Alps, but are,
as a rule, absent from the plain of Northern Europe. Professor J. Geikie
goes so far as to state (p. 398) that it was unlikely that southern
England during the climax of the glacial cold h