ALPINE SCULPTURE. 233 



posed of large boulders, which interrupt the course of a 

 river and compel the water to fall over them in cas- 

 cades. They have in great part resisted its action since 

 the retreat of the ancient glacier which formed the 

 moraine. Behind the moraine is a lake-bed, now con- 

 verted into a level meadow, which rests on a deep layer 

 of mould. 



At Pontresina a very fine and instructive gorge is 

 to be seen. The river from the Morteratsch glacier 

 rushes through a deep and narrow chasm which is 

 spanned at one place by a stone bridge. The rock is not 

 of a character to preserve smooth polishing; but the 

 larger features of water-action are perfectly evident 

 from top to bottom. Those features are in part visible 

 from the bridge, but still better from a point a little 

 distance from the bridge in the direction of the upper 

 village of Pontresina. The hollowing out of the rock 

 by the eddies of the water is here quite manifest. A 

 few minutes' walk upwards brings us to the end of the 

 gorge; and behind it we have the usual indications of 

 an ancient lake, and terraces of distinct water origin. 

 From this position indeed the genesis of the gorge is 

 clearly revealed. After the retreat of the ancient gla- 

 cier, a transverse ridge of comparatively resisting ma- 

 terial crossed the valley at this place. Over the lowest 

 part of this ridge the river flowed, rushing steeply 

 down to join at the bottom of the slope the stream 

 which issued from the Rosegg glacier. On this incline 

 the water became a powerful eroding agent, and finally 

 cut the channel to its present depth. 



Geological writers of reputation assume at this 

 place the existence of a fissure, the ' washing out ' of 

 which resulted in the formation of the gorge. Now 

 no examination of the bed of the river ever proved the 

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



