The Geographical Journal (Journal of the Royal Geographical Society): Volume XII, No. 2 [‎276r] (54/154)

AN EXPLORATION IN 1897 OF SOME OF THE GLACIERS OF SPITSBERGEN. 145
carrying agent in cutting through the range. In the case of rivers, this
eating-hack process is well recognized and understood. I suggest that it
is likewise true of glaciers, though of course the phrase “ eating back ”
is used as descriptive of the effect produced, not of the glacier’s action.
The “ eating hack ” is caused by aerial denudation, not by glacial
erosion ; but if the glacier were not there to carry away the debris, the
processes of aerial denudation would he arrested by the accumulation of
debris.
The best instance I can quote of what seems a clear case of one
glacier robbing the neve basin of another is in the Karakoram mountains.
There the Biafo glacier drains a great snow-field, which appears geo
graphically to belong to the Hispar glacier. When the incredible
rapidity of denudation in those regions is remembered, it seems far
from impossible that the ridge which bounds the Hispar glacier on the
south extended unbroken, and not so very long ago, across the Biafo
glacier, and that the gap through which the Biafo glacier now draws
off the snow-field behind, is only of recent formation.
Few persons, however, are familiar with the geography of this
remote region ; it seems, therefore, best to illustrate the theory above
propounded, by some possible example nearer home. I cite, but with
diffidence, two cases from the Alps, where it seems possible that well-
known glaciers may have eaten back a gap through mountain ridges.
In both cases, no doubt, the eating back may have been done by water;
all that I assert is that, if not done by water, it would have been accom
plished by the glaciers which exist on the spot.
My first example is taken from the Mont Blanc range.* I suggest
that originally there may have been a glacier with its head near the
present summit of Mont Blanc, having for its left bank a ridge (or
plateau-edge) now represented by the Aiguille du Midi and other
aiguilles, the Aiguille Yerte, the Aiguille du Chardonnet, and the
Aiguilles Dorees; whilst its right bank was approximately coincident
with the modern watershed The boundary between adjacent drainage basins. as far as Mont Dolent, except between
Mont Blanc de Courmayeur and the Tour Konde, where it has been
broken away. This ancient drainage system has been broken down,
and now the snows of the upper reservoirs are all discharged by such
glaciers as the Mer de Glace or the Glacier d’Argentiere, which cut
across one or other of these old containing ridges or plateau-edges.
Ihus too, I suggest, the Upper and Lower Grindelwald glaciers and
the Eosenlaui glacier may have invaded the Oberland plateau and crept
back into the heart of the mountain mass, isolating as high individual
peaks the Wetterhorn and Schreckhorn. Originally they were mere
“ corrie glaciers, ’ plastered on to the north face of the plateau—-just such
* Herr Imfeld’s new map is the only one on which this theory can be properly
examined.
No. II.— August, 1898.] l