from the Scandinavian glaciers, would have
brought detritus and boulders to the lowlands. Scandinavia was then
connected with Scotland, and England with France.

FOOTNOTES:

[1] A very interesting piece of information has been given us, recently,
by Mr. Barrett-Hamilton on the Arctic Fox of Spitsbergen. In comparing
the skulls of Spitsbergen Foxes with those of Europe, he found that the
former are much smaller, and represent a distinct race or sub-species.
This small race he believes to be confined to Greenland, Iceland,
Spitsbergen, and Novaya Zemlya, whilst the larger one occurs in Europe,
Asia, and on the Commander Islands. This fact favours the view which I
have advocated in Chapter V., that the Arctic Fox in Europe is a
Siberian migrant, and did not come from the north with the Reindeer and
Arctic Hare.

[2] I have already expressed this view on p. 120.

[3] The occurrence of this species in Lough Neagh in Ireland, pointing
to a connection between the Irish Sea and the Baltic, will be referred
to later on; as also that of two allied forms in the Caspian Sea.

[4] For additional species with a similar range, _vide_ Nordquist.

CHAPTER V.

THE SIBERIAN MIGRATION.

In dealing with the British fauna in particular, I have drawn attention
to the fact that it is chiefly in the south of England that we find
fossil remains of eastern species of mammals in recent geological
deposits. We can actually trace the remains of these species and their
course of migration across part of the Continent towards Eastern Europe,
and as none of their bones have been discovered in the southern or
northern parts of our Continent, it must be assumed that their home lay
in Siberia, where many still exist to the present day, and where closely
allied forms also are found. Some of these Siberian migrants have
remained in England and on the Continent to the present day. Many have
become extinct. But the animals forming this eastern migration did not
all originate in Siberia, though I have sometimes spoken of them
collectively as Siberian migrants. There must have been other centres of
dispersion of species in Europe. We know that a very active centre of
development--at any rate for land-mollusca--lay in South-eastern Europe,
either in the Caucasus or in the Balkan peninsula, or more probably in
both. The Alps no doubt produced a number of species which have spread
north and south, and may in their wanderings have joined the Siberi