LAND SCULPTURE BY MOUNTAIN GLACIERS 373 



the cirques, may be described as a grooved upland (plate 19 A). 

 A further continuation of the process removes all traces of the 

 earlier upland, for the cirques intersect from opposite sides and 

 thus yield palisades of sharp rock pinnacles which rise on pre- 

 cipitous walls from a terraced floor. This ultimate product of 

 cirque sculpture by glaciers is called a fretted upland (plate 18 

 A and 19 B). 



The features carved above the glacier. The ranges of pin- 

 . nacles carved out by mountain glaciers have become known by 

 j various names of foreign derivation, such as arete, grot, aiguille 



FIG. 397. A col shaped like a hyperbola between Mount Sir Donald and Yogo 

 Peak in the Selkirks (after a plate by the Keystone Plate Co.). 



mountains, " files of gendarmes" etc. They may, perhaps, be 

 best referred to as comb ridges, and according to their position they 

 are differentiated into main and lateral comb ridges, as will be 

 clear from the second map of plate 19. 



With the gradual invasion of the upland upon which the cirques 

 have made their attack, the area from which winds may gather 



