800 ROLLIN D. SALISBURY 



These ridges were always near the ends of glaciers, and usually 

 concentric with their termini, where the termini were not cut off 

 by the waves. The surface ridges of debris, concentric with the 

 ends of glaciers, were especially conspicuous on some of the 

 glaciers on the north side of Northumberland Island, and on the 

 glacier at the head of Dexterity Harbor, on the west side of 

 Baffin Bay (Lat. 72"). 



Tlie making of lateral moraines. — Many of the North Greenland 

 glaciers carr}^ lateral moraines, the explanation of which is 

 certainly to be found along the lines just indicated. In general 

 the lateral margins of the glaciers do not touch the sides of the 

 valleys in which they lie. Indeed they are generally separated 

 from them by distinct intervals, and this holds well up to the 

 heads of the glaciers. Within the stretch where the lateral 

 margins of the glaciers do not touch the valley walls, lateral 

 moraines have their least development near the heads of glaciers, 

 where they are often absent, and their greatest near their lower 

 ends. The lateral moraines, therefore, could not have been 

 formed by the falling of debris from the valley slopes onto the 

 ice, for of this there is no possibility. The upturning layers, as 

 seen in cross-section, and the debris seen between these layers 

 (Fig. 23), seem to show conclusively that the lateral moraines 

 were formed by having material brought to the surface by the 

 upturning and up-moving layers of ice. In some cases three of 

 these lateral moraines lay side by side near the margin of a 

 glacier, though more than two were rare. This statement is not 

 to be construed to mean that this is the only way in which lateral 

 moraines are made, but it seemed to be the prevalent way in the 

 case of the glaciers seen in north Greenland. 



Glacier load and its relatiojis to movcme7it. — Professor Russell' 

 has called attention to the fact that the movement of ice is 

 influenced by the amount of debris which it carries. This 

 doctrine finds abundant confirmation in the north. The lower 

 part of the ice, which is well charged with debris, or altogether 

 full of it, seems to virtually lose its motion and to become the 



^ This Journal, Vol. Ill, p. 823. 



