have invaded the more central parts of
Europe from the south-west, without however being of Lusitanian origin.
Of the true Lusitanian mammals a typical example is the Rabbit. Then we
have a few birds and several interesting reptiles and amphibians. The
genus to which the Brimstone Butterfly belongs is also of south-western
origin. A number of Mollusca are mentioned which from their range
likewise indicate a Lusitanian origin. Most of our British Slugs and
many of our larger Snails belong to this group.

All these are merely a small remnant of what we received from
South-western Europe during the Miocene and Pliocene Epochs. But they
spread into many parts of Europe, and a few even crossed into Asia. The
antiquity of the Lusitanian element in our fauna is especially indicated
by the frequent recurrence of "discontinuous distribution" among the
species belonging to that section.

CHAPTER VIII.

THE ALPINE FAUNA.

We are told by Sir Archibald Geikie (p. 851) that "from the Pyrenees
eastwards, through the Alps and Apennines into Greece, and the southern
side of the Mediterranean basin, through the Carpathian Mountains and
the Balkan into Asia Minor, and thence through Persia and the heart of
Asia to the shores of China and Japan, a series of massive limestones
has been traced, which, from the abundance of their characteristic
foraminifera, have been called the Nummulitic Limestone. Unlike the
thin, soft, modern-looking, undisturbed beds of the Anglo-Parisian area,
these limestones attain a depth of sometimes several thousand feet of
hard, compact, sometimes crystalline rock, passing even into marble, and
they have been folded and fractured on such a colossal scale that their
strata have been heaved up into lofty mountain crests sometimes 10,000,
and in the Himalaya range more than 16,000 feet above the sea." "Nowhere
in Europe," continues the same author (p. 860), "do oligocene strata
play so important a part in the scenery of the land, or present on the
whole so interesting and full a picture of the state of Europe when
they were deposited, as in Switzerland. Rising into massive mountains,
as in the well-known Rigi and Rossberg, they attain a thickness of more
than 6000 feet." "By far the larger portion of these strata is of
lacustrine origin. They must have been formed in a large lake, the area
of which probably underwent gradual subsidence during the period of
deposition, until in Miocene times the sea once m