I have dwelt upon the recent work of geologists in the peripheral areas
of the drift-covered regions of northern Europe, because I think the
results obtained are of great interest to glacialists in this country.
And for the same reason I wish next to call attention to what has been
done of late years in elucidating the glacial geology of the Alpine
Lands of central Europe--and more particularly of the low-grounds that
stretch out from the foot of the mountains. Any observations that
tend to throw light upon the history of the complex drifts of our own
peripheral areas cannot but be of service. It is quite impossible to do
justice in this brief sketch to the labours of the many enthusiastic
geologists who within recent years have increased our knowledge of the
glaciation of the Alpine Lands. At present, however, I am not so much
concerned with the proofs of general glaciation as with the evidence
that goes to show how the Alpine ground-moraines have been formed,
and with the facts which have led certain observers to conclude that
the Alps have endured several distinct glaciations within Pleistocene
times. Swiss geologists are agreed that the ground-moraines which
clothe the bottoms of the great Alpine valleys, and extend outwards
sometimes for many miles upon the low-grounds beyond, are of true
glacial origin. Now these ground-moraines are closely similar to the
boulder-clays of this country and northern Europe--like them, they are
frequently tough and hard-pressed, but now and again somewhat looser,
and less firmly coherent. Frequently also they contain lenticular
beds, and more or less thick sheets of aqueous deposits--in some places
the stony clays even exhibiting a kind of stratification--and ever and
anon such water-assorted materials are commingled with stony clay in
the most complex manner. These latter appearances are, however, upon
the whole best developed upon the low-grounds that sweep out from the
base of the Alps. The only question concerning the ground-moraines
that has recently given rise to much discussion is the origin of the
materials themselves. It is obvious that there are only three possible
modes in which those materials could have been introduced to the
ground-moraine: either they consist of superficial morainic débris
which has found its way down to the bottom of the old glaciers by
crevasses; or they may be made up of the rock-rubbish, shingle, gravel,
etc., which doubtless strewed the valleys before these were occupied by
ice; or, lastly, they may have been derived in chief measure from the
underlying rocks themselves by the action of the ice that overflowed
them. The investigations of Penck, Blaas, Böhm, and Brückner appear to
me to have demonstrated that the ground-moraines are composed mostly
of materials which have been detached from the underlying rocks by
the erosive action of the glaciers themselves. Their observations
show that the regions studied by them in great detail were almost
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