102 THE ICE AGE IN NORTH AMERICA. 



T. C. Chamberlin, hereafter to be noted, in northern Green- 

 land. 



Some most remarkable facts concerning the termination 

 of numerous glaciers in northern Greenland and in Grinnell 

 Land and Ellsmere Land on the other side of Smith Sound are 

 reported by Professor Chamberlin and by General A. W. 

 Greely.* In both these regions the glaciers often terminate 

 in perpendicular, or projecting ice cliffs. So extensive and 

 marked are these in Ellsmere Land that they were termed the 

 " Chinese Wall.' 7 They extend across the country in an 

 east and west direction and form an escarpment from 200 to 

 300 feet high. Over the crest of the wall appear the snow 

 fields and snow covered mountains where the glacier has its 

 source. 



The explanation of this peculiar phenomenon is to be 

 found partly in the fact that the upper strata of the ice 

 move faster than the lower, tending to form a " breaker" 

 in the ice, such as appears on the crest of an incoming wave. 

 Partly also, as suggested by Professor Chamberlin, because 

 the low angle at which the sun's rays strike the ice causes 

 them to melt the lower dirt laden strata which attract the 

 heat, faster than the purer strata found near the top of the 

 ice. 



*A. W. Greely, "Report of Proceedings of U. S. Expedition to Lady 

 Franklin Bay," Washington, 1888, vol. i, pp. 274-296. 



