286 FRAGMENTS OF SCIENCE. 



existence of this fissure ; and it is certain that water, 

 particularly when charged with solid matter in suspen- 

 sion, can cut a channel through unfissured rock. Cases 

 of deep cutting can be pointed out where the clean bed 

 of the stream is exposed, the rock which forms the 

 floor of the river not exhibiting a trace of fissure. An 

 example of this kind on a small scale occurs near the 

 Bernina Grasthaus, about two hours from Pontresina. A 

 little way below the junction of the two streams from the 

 Bernina Pass and the Heuthal the river flows through a 

 channel cut by itself, and 20 or 30 feet in depth. At some 

 places the river-bed is covered with rolled stones ; at 

 other places it is bare, but shows no trace of fissure. The 

 abstract power of water, if I may use the term, to cut 

 through rock is demonstrated by such instances. But if 

 water be competent to form a gorge without the aid of 

 a fissure, why assume the existence of such fissures in 

 cases like that at Pontresina ? It seems far more 

 philosophical to accept the simple and impressive history 

 written on the walls of those gorges by the agent which 

 produced them. 



Numerous cases might be pointed out, varying in 

 magnitude, but all identical in kind, of barriers which 

 crossed valleys and formed lakes having been cut through 

 by rivers, narrow gorges being the consequence. One 

 of the most famous examples of this kind is the Finster- 

 aarschlucht in the valley of Hasli. Here the ridge called 

 the Kirchet seems split across, and the river Aar rushes 

 through the fissure. Behind the barrier we have the 

 meadows and pastures of Imhof resting on the sediment 

 of an ancient lake. Were this an isolated case, one 

 might with an apparent show of reason conclude that the 

 Finsteraarschlucht was produced by an earthquake, as 

 some suppose it to have been ; but when we find it to be 

 a single sample of actions which are frequent in the Alps 



