Prof. T. G. Bonney—Alpine Passes and Peaks. 541 
the St. Moritzersee ; hence the fall is only 15 in 10,000, or, roughly 
speaking, about seven feet in a mile. The Maloya Kulm is a very 
short distance from the head of the Silsersee, and is only a few feet 
higher than it; the height assigned to the lake being 5872 feet, and 
to the pass 5942 feet. I doubt, indeed, whether the latter measure- 
ment indicates the lowest point, and think that it would be possible 
to divert the waters of the Silsersee from the Black Sea to the 
Adriatic by a comparatively shallow cutting. But no sooner have 
we traversed this low ice-worn floor of rock than the scene changes 
in a moment; we are standing on the brow of a series of lofty cliffs ; 
the road swings away to the left to seek a less precipitous part of 
the enclosing head of the valley, to the floor of which—nearly a 
thousand feet below—it descends by a series of zigzags: To what 
are we to attribute this singular configuration: this flat, almost level 
trough driven right through the crest of the Alps, and terminating so 
abruptly at the brink of a range of precipices? There is the river 
valley—one which seems to suggest, nay, to demand, the action of 
strong torrents for its making—and no torrent is to be found, for 
the mountains from which it could flow have vanished, and instead 
of a ridge we have vacant air! 
Is this trough the work of glaciers? Certainly it bears every- 
where the marks of moving ice. Members of the School of Ramsay 
might cite its wide but shaliow lake basins as examples of the 
excavatory power of ice, and here, though I could point out some 
difficulties in the application of their theory, I should not be surprised 
if their claim were substantiated. But the glacier which exercised 
any erosive action on this trough can only have been formed by the 
fusion of ice-streams which descended from the mountains on either 
side. Hence it may have modified the superficial features, but in no 
case can it be said to have excavated the trough, because, as already 
stated, there is not even a ridge at its head. Suppose the trough of 
the Maloya covered deep with snow and ice, it is obviously impossible 
that this can have exercised any erosive force of importance in the 
direction of the flow of the Inn, because here it would be almost at 
rest. Moreover, we can prove that when the glaciers of the Alps 
were vastly greater than now, and the Maloya was thus buried, the 
actual watershed of the pass—that is, the ice-worn rock on which 
the Kulm hotel now stands—was swept by a glacier which had its 
origin among the peaks on the southern side of the watershed—one 
represented at the present day by the Forno glacier ; for on this rock 
are strewn erratics of the peculiar porphyritic granite which forms 
the crags on the western side of that glacier. We have only to 
stand on this ice-worn plateau among the erratics which mark the 
overflow of the southern ice-stream, to glance at one moment along 
the unbroken trough on the Swiss side, and the next down the steep 
crags into Italy on the other, in order to realize how slightly the 
glaciers of the Great Ice Age can have modified the pre-existent 
natural features of the district, and to justify us in assigning to them 
a very secondary place among the graving tools employed by Nature. 
What explanation, then, must be given of this singular trough ? 
