CERTAIN PHASES OF GLACIAL EROSION 



215 



sloping Fiescheriirn are steep ice-clad slopes— the upper cirque 

 walls. Dropping in turn from the Fiescherfirn to the Lower 

 Eismeer is the ice cascade in the center of the picture. To the 

 right beyond the range of this picture the level Eismeer plunges 

 over another ice fall toward the Lutchine valley below. The last 

 plunge, however, is perhaps more in the nature of a hanging valley 

 at the approach to the main valley. Cataracts due to the fall of 



Fig. 12.— Nearer view of the head of the level Furgg ice sheet and the Furggen 

 Grat, whose precipitous walls are being undermined. View from the Matterhorn 

 hut. Photo, by R. T. C. 



glaciers from hanging valleys into main valleys are frequent but 

 necessarily occur at or near the junction of the valleys. Cataracts 

 occurring at intervals along the course of a single ice stream are 

 presumed to be correlated with stoping action. 



Fig. 1 1 is introduced as an example of a flat plateau-like glacier- 

 covered tract intermediate between the mountain heights behind 

 it and the lower valley in front. This flat plateau covers an area 

 of approximately four square miles at a mean altitude of about 

 10,000 feet above the sea. Ice cascades descend toward the 



