64 GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



described. This has a breadth of 70 miles and an ave'rage length of 20 to 25 

 miles, with approximately i ,500 square miles of area. It is made up of four great 

 commensal glaciers, with an innumerable number of smaller ones. Farther 

 west there lies the Bering Glacier, known to be of the same type, but not }'et 

 visited and described. It is c^uite likely that this variety of glacier is more 

 common than has been recognized, since in addition to the Wenkchemna there 

 is the Horseshoe Glacier at the head of the adjoining Paradise Valley, with some 

 16 commensal streams, and the Asulkan in the Selkirks (plate xxxix, figure 2) 

 which represents a piedmont glacier in process of disintegration into its compo- 

 nent streams. If the ordinary Alpine glacier, with its tributaries, is compared 

 to a river, the body of a piedmont glacier should be thought of as an ice lake, 

 of greater or less magnitude. 



3. Nourishment. 



Each of the component streams of the Wenkchemna may be traced back to a 

 more or less well defined and fairly distinct patch of neve. This may be no 

 more than a cone of avalanched snow, or it may be a strip of permanent snow 

 field filling a couloir in the mountain side, or between two adjacent peaks. 

 The highest point of the Divide here is Mt. Deltaform, with an elevation of 1 1,225 

 feet, somewhat lower than Victoria. To the west, and closely connected with 

 Deltaform, is Neptuak (Allen's No. 9) with an elevation of 8,767 feet. East- 

 ward from Deltaform there occur in order No. 7 (10,648 feet), No. 6 (10,520 

 feet), No. 5 (10,018 feet) and No. 4 (10,028 feet). The northern face of this array 

 of peaks is very abnipt, furnishing only a nieager collecting area for the snow. 

 The sno\A'fall is probably not inaterially different from that at the head of the 

 Lake Louise Valley, where it is estimated as about 25 feet annually. That which 

 clings to the steep slopes during the winter is largely avalanched upon the glacier 

 below in the spring and early summer. The most of that which remains is melted 

 and but little survives the warm season. The snow accumulates along the 

 northern base of the range, where it is protected from the noonday sun, allowing 

 it to become converted into nev^ and compacted into ice. Owing to the increased 

 altitude of the glacier's surface toward the west there is a gi^eater deposit along 

 the base of Deltaform and Neptuak (plate xxi). This rather meager supply of 

 snow could svipport a glacier of such dimensions only because of certain favorable 

 conditions. Being in the lee of some 3,000 feet of nearly vertical cliff, its neve 

 field is sheltered from the noonday sun, while that portion which is exposed is 

 almost completely veneered with a protective covering of rock debris. The 

 form of glacier, with the ice streams lying side by side, reduces the lateral melting 

 to a minimum, while the slope of the valley floor, upon which the glacier rests, 

 is sufficiently gentle to allow the ice to remain in a very sluggish condition. 



4. Drainage. 



Because of the conditions just outlined the amount of ablation is reduced 

 to a minimum and the surface drainage streams are coiTespondingly small and 



