CERTAIN PHASES OF GLACIAL EROSION 



201 



head-work in the cirques are lost in the more familiar body-work 

 and tail-work of the more accessible parts. Various stages and 

 transitions are shown in the accompanying photographs. 



Fig. 4 shows five well-developed basins escalloped in a hillside. 

 The two hollows on the left are round and wide and terminate 

 below in well-defined platforms or steps at nearly the same level. 



Fig. 5. — A concave scallop on the brow of a projecting embossment. Apparently 

 this is the work of sapping by the ice at the base of the cliff. Note the rounded convex 

 glacier-polished outlines of the rest of the embossment. In the background is the 

 Lyskamm, central Pennine Alps. Photo, by R. T. C. 



They are approximately as wide as they are long, showing that the 

 ice which accumulated there has eaten its way in a distinctly 

 broad fashion into the rock slope on which it lay. The vertical 

 distance which any given part of the ice has moved its rock is 

 small relative to the total amount of transportation accomplished. 

 The work has been done very locally compared with the longitudinal 

 movement of typical water action. The next two basins continue 

 down the slopes to points much nearer to the sea. There has been 



