THE ESKERS OF NOVA SCOTIA. PREST. 387 



drainage, and receiving the flow of water and sediment 

 from above its level, the esker becomes in time an immense 

 bank of water worn gravel, like those on the Ashuanippi 

 and other rivers in Labrador. This condition would un- 

 doubtedly continue until the disappearance of the ice from 

 the low lands allowed the sediment-charged waters to retire 

 to their present beds. Thus all features of eskers are account- 

 ed for except those due to the most recent action of the 

 present streams. 



A. C. Lowe and others, in their explorations of Northern 

 Canada, note the immense eskers of Labrador, especially- 

 one of 100 miles long, hundreds of feet wide and 40 to 60 

 feet high. The Hamilton, Ashuanippi and Dobuant Rivers 

 are noted for their great valley eskers as well as other smaller 

 but well developed ones on higher ground. Like all other 

 valley eskeis, they owe their birth and growth to a crevasse 

 which formed when that part of Canada was still under 

 the northern. ice sheet. 



Transverse Crevasses. — The larger visible crevasses of 

 Arctic and Antarctic regions were formed across the course 

 of ice movement, just as in Nova Scotia and most important 

 eskers lie across the courses of both drainage and ice move- 

 ment. What deposits these great crevasses actually contain 

 will be unknown until a future interglacial age lays bare 

 the earth probably 5,000 feet beneath the present surface. 

 That they contain debris is both possible and probable, as 

 we know that the edges of these crevasses have the same 

 eroding power as the edge of the ice front. This, however, 

 we cannot see. 



The Crevasse Theory of the Origin of Eskers. — But this 

 we know: 



1. That the visible crevasses run across the course of 

 ice movement as the majority of our eskers do, 



2. That they cut across all minor undulations as our 

 eskers do. 



Proc. & Trans. N. S. Inst. Sci., Vol. XIV. Trans. 25 



