ALPINE SCULPTURE 251 



produced by small streams the beds of which are dry for 

 a large portion of the year. Right and left of the larger 

 gorges such secondary chasms are often found. The idea 

 of time must, I think, be more and more included in our 

 reasonings on these phenomena. Happily, the marks 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 effected 

 in geologic periods. Thus the modern portion of the Yia 

 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 traveller passes along the side of the chasm midway 

 between top and bottom. Whichever way he looks, back- 

 ward or forward, upward or downward, toward the sky or 

 toward the river, he meets everywhere the irresistible 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- 

 barriers 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 

 themselves? 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 



