702 ALPINE VALLEYS IN RELATION TO GLACIERS. [ Noy. 1902, 
support from facts, but also the Alpine valleys are almost wholly 
pre-Glacial. The upper and broader parts—say those higher than 
800 feet, more or less, above the present beds’—are chiefly pre- 
Pliocene work; the narrower (V-like parts) below were formed in 
part of that Period; the gorge-cutting dates from later Pliocene 
onwards; while the superficial moulding, some shallow tarnsin special 
situations, the roches moutonnées and the general smoothing, 
are the work of the Ice-Age. Many upland valleys were cut down 
to the curve of no-erosion at an early date—perhaps even by the 
beginning of Pliocene times; though in others denudation might 
be again started by the change in level which closed the Miocene 
Period. Except for the cutting of gorges and the destruction, 
of peaks and crests, denudation in the Alpine regions now pro- 
ceeds with comparative slowness,” and many streams over the 
greater part of their course are actually raising, instead of lowering 
their beds. 
EXPLANATION OF PLATE XXXvV, 
Fig. 1. Section along the bed of the Visp, from the Monte-Moro Pass to near 
Visp, on the scale of § inch to the mile. 
2. Section across the Saas Valley, from Grundberg to the Alphubel, on the 
scale of 14 inches to the mile. 
These sections have been constructed from the contour-lines in the 
‘Topographischer Atlas der Schweiz,’ without any attempt to indicate 
cliffs or minor irregularities. As the second one crosses the Visp very 
obliquely, it materially diminishes the lower slope on either side. 
From Saas Grund to Saas Fee is a really steep ascent ; in other words, 
the true section of this part of the valley is more V-like than it 
appears in the diagram. 
I. Section of glaciated valley, according to Prof. W. M. Davis. 
II. Section of glaciated valley, according to the author. 
AB = Bed of pre-Glacial valley; C= Glacial valley ; 
QR= Highest level of glacier. 
= 
[For the Discussion, see p. 716.] 
It is impossible to give a very precise figure—according to circumstances, 
it may be more or considerably less. 
> In the latter case I should think that it was most generally active from rather 
under 8000 to over 9000 feet. Above this limit, generally speaking, only cliffs 
are exposed, the slopes being protected by snow. 
