GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 67 



the lateral and the frontal moraine. They end in a peculiar series of short 

 closely pressed ridges, slightly concave outward. 



Since a glacier of this kind cannot be said to have an end, the term frontal 

 may be more appropriately applied to the rock debris that is being dumped 

 along the united extremities of the individual ice streams. Were the glacier 

 to begin a uniform retreat from its present position, there would be left a ridge 

 of angular rock debris, over three miles in length, marking the shape and present 

 position of the front. Inside of this would be left upon the valley floor the debris 

 which now mantles the surface of the ice, or is contained within. Because of 

 the very slow advance, to be noted below, the frontal morainic material over 

 the eastern half is being very slowly urged forward, giving a steep and unstable 

 frontal slope, but not so steep that it can not be climbed at almost any point. 

 At only one point, nearly opposite peak No. 7, is there any ice showing and 

 here the de"bris cover is partially lacking. Should the ice front actually halt a 

 frontal moraine would form very slowly, in spite of the amount of ddbris carried, 

 because of the sluggish condition of the ice. Toward the western side the front 

 becomes less steep and high and finally merges into the neVe and snow bank 

 which mantles the col between Neptuak and Hungabee. 



6. CREVASSES. 



The glacier is remarkably free from crevasses in the lower part and about the 

 sides. In the case of the commensal streams, measurements would probably 

 show that the sides were moving forward at about the same rate as the centers, 

 so that there is lacking that differential movement that gives rise to marginal 

 crevasses. The mutual pressure from the sides is sufficient to prevent the 

 opening of radial crevasses along the front. The absence of prominent transverse 

 crevasses indicates that the bed is of even slope and the motion slow enough 

 to allow the ice to yield, without rupture, to most of the inequalities that do 

 exist. The absence of crevasses in this case is quite as instructive as their pres- 

 ence would be. Upon the steeper portions of the neVe" slopes there occur nu- 

 merous transverse breaks of the nature of bergschrunds, caused by the upper mass 

 clinging, for the time being, to the rocky wall while the lower portion draws 

 away from it. If kept under inspection these schrunds would be found to close 

 up, as they work their way down the slope and to open again at a higher level. 



7. MOVEMENT ABOUT THE FRONT. 



In a little booklet prepared for the Canadian Pacific Railway by Messrs. 

 George and William Vaux, and entitled Glaciers, attention was first called 

 to the evidence that this glacier is advancing into the adjoining forest. No 

 data were at hand for determining the amount of this forward movement, or 

 whether it is still in progress. Dead trunks of forest trees, from which the 

 bark and branches have fallen, are seen projecting from near the frontal slope 

 (plate xxiv, figure i). Some of these trees were probably killed by a forest fire 



