lOO GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



crevasses, which lie at right angles to the mafe direction of flow, the n^v^ that 

 accumulates between this minor peak and Leda (9,133 feet) moves northward 

 and nourishes the middle ice stream. The oblique course is taken probably 

 because of the continuation southward of the ridge of rock previously noted 

 as separating the middle and eastern streams. The presence of a similar ridge 

 beneath the ice deflects the neve snow and ice from the northern slopes of Castor 

 (g,io8 feet) and Pollux (9,176 feet), to which is added that from the Dome 

 (9,029 feet), and thus is obtained the supply for the double-nosed western ice 

 stream. The middle stream is least well supplied at the present time with ice 

 from the ndv6 field and has receded farthest. It seem.s very probable that 

 when the ice was thicker over the n^v^ there was relatively less of it deflected 

 to the western stream by the subglacial ridge and this fact peiTnitted the middle 

 stream to maintain the same length as the now better nourished eastern. The 

 superficial layers from Castor and Pollux could move directly across those which 

 the configuration of the bed deflected northward, but as the general elevation of 

 the nev6 was lowered a relatively greater and greater percentage of ice was 

 deflected to the western stream and the nose of the middle stream retreated 

 steadily some 2,200 feet up the slope, to an elevation at present 400 feet higher 

 than the nose of the eastern stream. Were the ice of all three streams now 

 concentrated into a single one it is probable that the nose would attain as low 

 an altitude as that of the lUecillewaet. 



4. Moraines. 



Owing to the absence of high, overtowering cliffs, such as we find in the 

 case of the Wenlvchemna and Victoria glaciers, the n6v6 fields of the Asull<:an 

 receive very little rock debris over their surfaces. In consequence, the ice itself, 

 except along the margins, is quite free from rock fragments. As in the case 

 of the neighboring lUecillewaet collecting basin, conditions are favorable for 

 receiving wind-blown dust from peaks and ridges towering above the snow. 

 This dust is distributed somewhat evenly over the snow and, when concentrated 

 by melting, gives rise to the stratification and iinparts a soiled appearance to the 

 ice about the lower margins. 



The right lateral moraine of the eastern ice stream makes its appearance just 

 east of the nose and south of the stream from Asulkan Ridge. It rises at once into 

 a conspicuous, sharp-crested ridge, extending south-southwestward, and bending 

 abruptly to the south-southeast, attaining the length of a mile before it dips 

 under the n6ve snow. The lower portion of the moraine seems entirely free 

 from ice, the outer slope carrying fir and spruce 50 to 60 years of age. The inner 

 slope is more steep and has younger vegetation, indicating that the ice has within 

 a few decades withdrawn from the moraine. The crest rises to a height of 60 to 

 70 feet above the valley floor upon which the glacier rests. The rocks consist 

 largely of bruised and rounded quartzites and schists, which in the upper part 

 are embedded in a matrix of glacial clay. This material appears to come 

 from beneath the glacier that covers the western slope of Asulkan Ridge, 



