hanistan. In following a westward
course, the emigrant was compelled to keep along the northern shore of
it. We do not know the state of the physical geography of the region
between the Black Sea and the Tianshan Mountains, but it seems certain
that a considerable extent of dry land enabled a wanderer from Central
or Southern Asia to reach the Balkan peninsula by skirting the northern
shore of that large miocene sea. No miocene deposits occur north of
Teheran or of the Upper Euphrates, nor are they known from the islands
of the AEgean Sea or the lands surrounding it. From the Balkan peninsula
it was possible for our migrant to reach the European Alps, which were
then slowly rising as a peninsula out of the western portion of the
great miocene sea. What are now the Alps was then hilly ground, which
was being raised from the bottom of the sea. It was no doubt connected
with the Balkan peninsula, so that an intercourse of species could take
place between this newly-formed peninsula and Central Asia. I say
peninsula, because the miocene sea almost completely surrounded it. From
the Western Mediterranean a wide gulf extended up the Rhone valley into
that of the Rhine as far north as Maintz. Then skirting along the
northern outliers of the Tyrol, the gulf can be followed as far east as
Transylvania. It is quite probable that it extended much farther east
still, but there is as yet no geological evidence forthcoming. At any
rate, our Asiatic migrant turning northward from the Balkan peninsula
found its farther progress barred once more by an arm of the same sea
which in its earlier peregrinations had stopped it from going south (cf.
Suess, i., p. 406).

In later miocene times the sea does not seem to have surrounded the
Alps to the same extent as it did before, but it certainly extended from
the Eastern Alps to the shores of the Sea of Asov, so that the direct
northward passage was still more or less barred to the Oriental
immigrants. At the same time Alpine species were now able to emigrate to
the North European provinces. During the last stages of this epoch, the
same sea increased its area very considerably in an eastward direction.
One continuous expanse of water now stretched from the Alps as far as
the Sea of Aral in Central Asia, perhaps even farther.

During pliocene times especially, the northern parts of the Balkan
peninsula were occupied by a series of freshwater lakes, while Greece
was joined to Southern Italy, Si