ntinuous ocean extends
from the east coast of England across Holland, Northern Germany, and
Russia to the White Sea. At the same time Greenland and Northern
Scandinavia, Scotland and Southern Scandinavia, are united by a narrow
strip of land, and so are England and France. The waters of the Atlantic
and this North European Sea do not therefore intermingle at any point,
the two seas being absolutely independent of one another.

Such I assume to have been the geographical condition of Northern
Europe during the deposition of the Red Crag. Arctic mollusca were then
brought to the east coast of England, and boulders were scattered
through the beds laid down on that coast by icebergs which had been cast
off by Scandinavian glaciers on reaching the sea. Bedded clays which
have yielded arctic shells lie beneath the lower continental
boulder-clay on the Baltic coast-lands and on the coast of the White
Sea. According to Professor Geikie, marine clays on the same geological
horizon reach an elevation of some 230 feet. "It would seem, then," he
says, "that before the deposition of the lower boulder-clay of those
regions the Baltic Sea had open communication with the German Ocean" (p.
442). All these clays are evidently deposits of the same sea. But apart
from the fact that the Red Crag and these Baltic deposits are the oldest
of the upper Tertiary beds containing arctic shells, there is no
evidence that they are contemporaneous.

Overlying the same Baltic deposits comes the lower boulder-clay,
reaching a thickness of several hundred feet in some parts of Germany.
It presents, like the upper clay, frequent interstratification with
well-bedded deposits of sand and gravel. The scarcity of marine
mollusca, the occurrence of striated surfaces, and the occasional
presence of so-called giants' kettles, appear to favour the view, which
at present is generally adopted by both British and Continental
geologists, that the boulder-clay owes its origin to land-ice. I have
stated on several occasions that the view of the marine origin of the
boulder-clay agrees best with the known facts of distribution, and with
the history of the European fauna (pp. 80-86, and p. 129). It may be
urged that if the lower boulder-clay were contemporaneous with the
British Crags which succeeded the Red Crag, how can we explain the fact
that these crags contain plenty of shells, while in the lower
continental boulder-clay there are scarcely any?

But as yet our