n Europe under such conditions, as there were no areas free from
ice. A more vivid idea of the state of Europe during the epoch of
maximum glaciation will be obtained by looking at Professor Geikie's map
(p. 437). The whole of Scandinavia, Iceland, Scotland, Ireland, and
Switzerland is there represented as having been completely enveloped in
ice, and also the greater part of Russia, Germany, and England. In
speaking of Scandinavia (p. 424) he remarks that "the whole country has
been moulded and rubbed and polished by one immense sheet of ice, which
in its deeper portions could hardly have been less than 5000 feet or
even 6000 feet thick." The greater portion of the area indicated as
having been underneath a sheet of ice is thickly covered with
superficial accumulations of gravel, sand, and clay. The latter is
generally spoken of as "boulder clay," and, with the associated sand and
gravel, it may be observed equally well in Russia or Germany, in England
or Ireland. As a rule these stony clays thicken out as they are traced
from the high-lying tracts to the low grounds; and especially near the
mountains the rock-surfaces are often polished and striated. "For many
years it was believed," continues Professor Geikie (p. 432), "that all
those superficial deposits were of iceberg origin. The low grounds of
Northern Europe were supposed to have been submerged at a time when
numerous icebergs, detached from glaciers in Scandinavia and Finland,
sailed across the drowned countries, dropping rock-rubbish on the way.
Such was thought to have been the origin of the erratics, stony clay,
and other superficial accumulations, and hence they came to be known as
the 'great northern drift formation.'" "But," he adds (p. 433), "when
the phenomena came to be studied in greater detail and over a wider
area, this explanation did not prove satisfactory. The facts described
in the preceding paragraphs--the occurrence of striated surfaces and
_roches moutonnees_, the disturbed appearances associated with the till,
and the not infrequent presence of giants' kettles--convinced geologists
that all the vast regions over which boulder-clay is distributed were
formerly occupied by the 'inland ice' of Scandinavia."

I think Professor Geikie over-estimates the value of the evidences which
appear to be in favour of his theory. His treatise on the Ice Age leaves
one under the impression that the older view of the marine origin of the
boulder-clay is not onl