20 GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



giving rise to a series of transverse crevasses. The lower one and one-half 

 miles of the Victoria presents a remarkably even surface slope, suggestive of a 

 correspondingly even bed, so that it may be ascended with entire safety by the 

 most inexperienced. The nose reaches an altitude of about 6,000 feet, so that 

 the average slope is at the rate of about 1,200 feet to the mile. For the lower 

 half the surface slope is but 650 to 700 feet to the mile, or at the average rate 

 of 7 to 8. 



In the neVe" region the surface of the glacier is concave, owing to the accu- 

 mulation of snow along the base of the cliffs, this being permitted by the 

 relatively small amount of heat radiation and reflection. For a short distance 

 opposite Lefroy the cross sections of the ice stream have a horizontal surface 

 line, while in the lower portion the. surface is flatly convex, owing to the lateral 

 melting caused by the rock walls and, to a greater or less extent, by the lateral 

 drainage streams. (See the cross-section of the Victoria along the line of the 

 steel -plates, page 30.) It does not seem probable that the glacier attains 

 any considerable thickness, the thickest portion, apparently, lying opposite the 

 tributary where the ice may be 500 to 600 feet in depth. The nose is rounded, 

 completely veneered by rock debris so as to conceal the ice, and perched up 

 above the valley floor upon an old moraine which it has partially overridden,' 

 but has not had the strength to push aside (plate v, figure i). The front here 

 is steep, the angle being about 38, and about 90 feet in height, with a series of 

 gradually rising crests from the medial and right lateral moraines. Back from 

 this nose some 2,000 feet, there is exposed a steep ice wall, 35 to 50, which 

 attains a height of 125 feet, and continues for about 800 feet. This now appears 

 as the side of the glacier, but the position and form of the older moraines show 

 that the front has been gradually swinging around into this oblique position, 

 the cause of which is apparent from an inspection of the map. The eastern 

 side of the glacier is much better protected by the right lateral moraine and by 

 the much broader and closely placed medial. This portion of the front is thus 

 prevented from melting, while the less well protected western half has been 

 rapidly receding. Between this oblique ice wall and the real nose other smaller 

 faces are developing and being enlarged with each season's melting. 



2. NOURISHMENT. 



The main glacier is nourished in four ways, which may be separately recog- 

 nized, as follows: 



a. By the moisture directly precipitated into the valley between Mts. 

 Victoria and Lefroy. The great bulk of this is in the form of snow, which 

 probably amounts to about 25 feet per annum. The lesser amount in the form 

 of hail, rain, dew, fog, and frost would also contribute to the substance of the 

 glacier. 



b. The funnel-like form of the valley, with its opening to the north, enables 

 it to catch and retain large quantities of snow drifted southward by the north 

 winds,- as well as that which collects in the lee of Victoria when a west wind is 



