GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 57 



melting, the block settles into its position of equilibrium and the making of a 

 glacial table begins anew. In exceptional cases the undercutting of the pedestal 

 may be done by a surface stream. In the case of 25 tables selected at random, 

 it was found that the longer of the horizontal axes of the pedestals had an average 

 magnetic bearing of N. 36° W., or 11° W. of true north. With a larger, or a 

 different, series, the average would probably be more nearly the true north. 



j. Surface lakelets. Upon the middle portion of the Victoria, western side, 

 where the ice is presumably quite stagnant, there occurs a series of surface 

 lakelets, the crater-like basins of which have been hollowed in the ice. The 

 largest of this series is somewhat elliptical in form, 200 feet long by 100 feet 

 broad (plate xix, figure 2), and filled with deep blue water in which miniature 

 ice-bergs may be seen floating about. The southern and eastern banks of the 

 lakelet are from 12 to 20 feet high and under cut, apparently by the melting 

 action of the lake water. The northern and western banks have been acted 

 upon more strongly by the sun, causing them to recede and the d6bris to slide 

 down until the margins of the lake are filled and the ice banks veneered sufficiently 

 to retard melting (plate xix, figure 2). These banks ai^e as steep as the debris 

 can stand and from 25 to 30 feet in height. From the still steeper ice walls 

 the gravel and small boulders are splashing into the water with a sound suggestive 

 of considerable depth. The lake has no visible outlet and persists from season 

 to season. Several similar lakelets, but smaller, occur in the same vicinity, 

 some having their sides completely veneered with rock debris, which has checked 

 melting and allowed the lakelet to become almost dry. 



These lakelets may have originated in marginal crevasses and been enlarged 

 and shaped by melting, or they may have originated by surface melting over 

 certain limited areas less well protected by debris covering. In the preceding 

 discussion of debris cones it was shown how miniature basins might originate. 

 In a stagnant portion of the glacier it is possible that the basins of such lakelets 

 might arise in a similar manner from such a mound as that figured from the 

 Wenkchemna Glacier (plate xix, figure i). The rock debris rolling or sliding to 

 the base would leave the cone sufficiently bare to permit rapid melting to a depth 

 at which the marginal debris would begin to slide back again. The accumula- 

 tion of the debris in the basin would check further melting at the center, while 

 the surrounding ice has lost, in proportion, a part of its debris. As observed by 

 Russell upon the Malaspina, the surrounding ice would be lowered until the basin 

 disappeared and what had been the centre of the basin would become the crest 

 of a boulder mound. If conditions remained favorable, i.e., sufficient thickness 

 of stagnant ice and continuous surface ablation, the sides of the mound would 

 become more and more steep, as it gained in height and the time would come 

 when the bulk of the debris would slide or roll to the base, the ice core would 

 be removed to the general level and a new basin would be started. For the 

 larger lakelets the complete cycle would probably have to be reckoned in decades 

 and centuries. 



k. Rock reflection (?). A final surface feature remains to be described, al- 



