ore overflowed the
area."

From these remarks by our most eminent British geologist, we gather that
in early Tertiary times much of the present area of Switzerland was
either a sea or a large freshwater lake. The Alps were then appearing in
this sea, probably as a chain of islands, and in the beginning of the
Miocene Epoch one large elongated island had made its appearance--the
future European Alps. I have already mentioned that the Miocene Sea
skirted the Alps from the Mediterranean up the valley of the Rhone and
along its northern and eastern margin. Miocene marine deposits are also
known from the Southern Alps and the east side of the Apennines, from
Corsica, Sardinia, and Malta. No trace, however, of them has been
noticed anywhere along the AEgean Sea or on the Balkan peninsula. The
Alps were therefore connected to the east with the outliers of the
Balkan Mountains, and in this way with Asia, from which they received so
large a proportion of their fauna and flora. In pliocene times the sea
still washed the southern shore of the Alps, but to the north dry land
gradually supplemented the sea, and the Alpine fauna and flora were
able to pour into the plain. It was then that the Arctic species--which
we have learned had migrated into Northern Europe from the north--found
their way to the Alps. In a similar way Lusitanian forms--in fact,
species from almost all parts of Europe--were now free to wander to the
newly opened up peninsula which had become part of the mainland of
Europe. The typical Siberian species had not entered our continent at
that time, it was not till much later--not until the middle of the
Pleistocene Epoch--that they made their appearance at the foot of the
Alps, but, as we shall see later on, it is doubtful whether many of
these species ever reached the mountains.

The fauna of the Alps, and also the flora, is therefore made up of a
number of component elements. In the first place we have the Oriental
element--the migrants from Central and Southern Asia. When the nature
and origin of the Oriental fauna in Europe was discussed, reference was
made to the fact (p. 272) that we can distinguish an older from a newer
Oriental migration. Both of these have entered the Alps. As we might
anticipate, many of the older Oriental migrants have developed into new
species, laying the foundation of an indigenous Alpine element. From the
fact that they set foot on the Alpine peninsula, it might be expected
that the