owing
chiefly to extensive subsidences having taken place. Only very recently,
says Professor Suess, did the whole of the AEgean continent subside (i.,
p. 437). Huge cliffs of levantine freshwater deposits now mark the new
coast-line, and the Mediterranean advances steadily towards the Black
Sea and the Sea of Asov. A new order of things is now established,
continues the famous author of _Das Antlitz der Erde_; where there were
high mountains we now behold a deep sea, in some places many thousand
feet deep. All this took place quite recently,--geologically
speaking,--certainly in post-glacial times; and man may even have
witnessed these imposing events. Most geologists admit the correctness
of these views. They are, moreover, built upon such solid geological
evidence, that even if the science of zoogeography had not yet taught us
anything, naturalists would not hesitate in accepting them.

Animals and plants were free to migrate from Central and Southern Asia
to Greece by land for untold ages. The vast accumulation of mammalian
bones which have been discovered at Pikermi, and so ably described by
Gaudry, are probably to a large extent the remains of Asiatic immigrants
to Europe. Many of these resemble forms still living in South Africa,
which implies that a highway existed also at that time between Asia and
Africa. Among these is a giraffe and antelopes closely allied to
African species, and other most interesting mammals.

In still earlier European deposits--the Miocene--we find the ancestors
of modern Elephants, which are probably of Asiatic origin. The remains
of several kinds of monkeys occur, whose nearest relations are now
confined to Southern Asia. Altogether the fauna bears a strong Asiatic
facies. Many of our European terrestrial invertebrates probably arrived
about this time from Asia. The struggle for existence being keener and
the facility for migration much greater in the higher vertebrates,
they--or at any rate the mammalian faunas--were subjected to more rapid
changes than the invertebrates. I have repeatedly expressed my belief
that a great number of our familiar insects and mollusca inhabited
Europe long before our present mammals came into existence.[2]

Let us now follow one of the miocene Oriental migrants starting from
Central Asia on its way to Europe. Very soon after leaving its home, it
must have encountered a sea which extended at that time from the Eastern
Mediterranean to the borders of Afg