GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



dates of observation. Exactly one year later (August 27, 1905) the nose had 

 made a retreat of 34 feet from the position held in 1904, standing now 21$ feet 

 back from the reference line established in 1899. The nose consisted at this time 

 of a thin slab of ice, sloping to the west and coated with fine debris. A relatively 

 small amount of melting would cause a further recession of 30 to 35 feet. The 

 ice in the left lateral moraine was found to extend four feet beyond the reference 

 line and 25 feet beyond the nose. Owing to the rock cover it could not be 

 ascertained how much farther the morainic ice core extended. The movements 

 of this nose may be summarized as follows: 



CHANGES IN THE NOSE OF THE ASULKAN GLACIER. 



(Eastern Ice Stream.) 



1898-1899. "Practically no change." 



1899-1900. Recession of 24 feet. 



19001901. Advance of 4 feet. 



1901-1903. Average advance of 18 feet. 



19031904. Retreat of i foot. 



1904-1905. Retreat of 34 feet. 



1905-1906. No change. 



9. FORMER ACTIVITY. 



a. Development and decadence. At a much earlier stage, presumably in 

 Pleistocene time, the combined snows of the Asulkan Valley united into a great 

 Alpine glacier, the ancient Asulkan, which was a tributary of the ancient Ille- 

 cillewaet, and this, in turn, a tributary of the great trunk glacier that flowed 

 southward in the Columbia Valley, to the west of the Selkirks. With the diminu- 

 tion of snowfall, and possibly also an amelioration of the climate, the glaciers 

 disappeared from the main valleys and withdrew into the tributary valleys 

 and alongside the steep, higher slopes. An Alpine glacier occupied the Asulkan 

 Valley from the Pass to where the valley joins the Illecillewaet, some four 

 miles in length, which was in part nourished by a hanging, piedmont glacier 

 extending from the Pass to Mt. Abbott. This glacier sustained, during this 

 stage, the same relation to the Asulkan lying in the valley, that the hanging 

 Victoria sustains to the lower ice stream. The effect of these great ice masses 

 upon the valley floor and sides was similar to that already discussed for the 

 Victoria and Yoho glaciers (pages 61 and 80). 



b. Bear-den moraines. Just before the complete and final separation of the 

 Asulkan from the Illecillewaet, the Asulkan became loaded with very coarse, 

 angular rock fragments , and only a minimum of fine material. This was at the same 

 time that the Illecillewaet was similarly laden and, conjointly, they deposited 

 the massive bear-den moraine described upon page 96. The most of its 

 material was deposited upon its right, showing that it must have been received 

 from the western side of Glacier Crest and Mt. Lookout. The amount carried 

 was notably less than that brought down by its neighbor lying to the east of the 

 Crest. The ridges about the head of the valley and along the western side were 

 largely under snow and ice and could supply no such debris. After this load 



