ALPINK SCULPTURE. 181 
which the rivers have, in most cases, left behind them, and 
which refer, geologically considered, to actions of yesterday, 
give us ground and courage to conceive what may be ef- 
fected in geologic periods. Thus the modern portion of the 
Via Mala throws light upon the whole. Near Bergiin, in 
the valley of the Albula, there is also a little Via Mala, 
which is not less significant than the great one. The river 
flows here through a profound limestone gorge, and to the 
very edges of the gorge we have the evidences of erosion. 
But the most striking illustration of water-action upon 
limestone rock that I have ever seen is the gorge at Pfaffers. 
Here the traveler passes along the side of the chasm mid- 
way between top and bottom. Whichever way he looks, 
backward or forward, upward or downward, toward the 
sky or toward the river, he meets everywhere the irresist- 
ible and impressive evidence that this wonderful fissure has 
been sawn through the mountain by the waters of the 
Tamina. 
I have thus far confined myself to the consideration of 
the gorges formed by the cutting through of the rock-bar- 
riers which frequently cross the valleys of the Alps; as far 
as they have been examined by me they are the work of 
erosion. But the larger question still remains, To what 
action are we to ascribe the formation of the valleys them- 
selves? This question includes that of the formation of 
the mountain-ridges, for were the valleys wholly filled, the 
ridges would disappear. Possibly no answer can be given 
to this question which is not beset with more or less of 
difficulty. Special localities might be found which would 
seem to contradict every solution which refers the con- 
formation of the Alps to the operation of a single cause. 
Still the Alps present features of a character sufficiently 
definite to bring the question of their origin within the 
sphere of close reasoning. That they were in whole or 
in part once beneath the sea will not be disputed; for they 
are in great part composed of sedimentary rocks which re- 
quired a sea to form them. Their present elevation above 
the sea is due to one of those local changes in the shape of 
the earth which have been of frequent occurrence through- 
out geologic time, in some cases depressing the land, and in 
others causing the sea-bottom to protrude beyond its sur- 
face. Considering the inelastic character of its materials, 
the protuberance of the Alps could hardly have been pushed 
