ACTION OF TORRENTS. 267 
leap at once from the flanks of the mountains upon the plains 
below. This arrangement of surfaces naturally facilitates the 
formation of vast deposits at their points of emergence, and the 
centre of the accumulation in the case of very small torrents is 
not unfrequently a hundred feet high, and sometimes very 
much more. 
The deposits of the torrent which has scooped out the Nant- 
zen Thal, a couple of miles below Brieg in the Valais, have 
built up a semicircular hillock, which most travellers by the 
Simplon route pass over without even noticing it, though it is 
little inferior in dimensions to the great cones of dejection 
described by Blanqui. The principal course of the torrent hay- 
ing been—I know not whether spontaneously or artificially— 
diverted towards the west, the eastern part of the hill has been 
gradually brought under cultivation, and there are many trees, 
fields, and houses upon it; but the larger western part is furrow- 
ed with channels diverging from the summit of the deposit at 
the outlet of the Nantzen Thal, which serve as the beds of the 
water-courses into which the torrent has divided itself. All 
this portion of the hillock is subject to inundation after long 
and heavy rain, and as I saw it in the great flood of October, 
1866, almost its whole surface seemed covered with an unbroken 
sheet of rushing water. 
The semi-conical deposit of detritus at the mouth of the 
Litznerthal, a lateral branch of the valley of the Adige, at the 
point where the torrent pours out of the gorge, is a thousand 
feet high and, measuring along the axis of the principal current, 
two and a half miles long.* The solid material of this hillock— 
which it is hardly an exaggeration to call a mountain, the work 
of a single insignificant torrent and its tributaries—including 
what the river which washes its base has carried off in a com- 
paratively few years, probably surpasses the mass of the stu- 
pendous pyramid of the Matterhorn. 
In valleys of ancient geological formation, which extend 
* SONKLAR, Die Octzthaler Gebdirgsgruppe, 1861, p. 231. 
