98 J. Parkinson — Lake Basins in Alberta ^ British Columbia. 



The geological structure of this district is described by Mr. E, G. 

 McConnell/ and it will be sufficient to refer to the salient points. 

 Mr. McConnell divides this region into two nearly equal parts, 

 taking the western side of the Sawback Eange as the line of 

 division. To the east of this line the dip is consistently to the 

 west, due to the fact that a thrust from that direction has produced 

 a series of roughly parallel ridges, which have been " tilted and 

 shoved over one another into the form of a westerly dipping 

 compound monocline." Eundle and Cascade Mountains, near Banff, 

 are examples of this type. On the western side as far as the 

 Columbia Eiver no reversed faults are found, and " ordinary and 

 overturned folds play the most important role," The lakes which 

 form the subject of the present note lie in the latter division some 

 two miles to the west of Laggan (5,008 feet). They are three in 

 number. Lake Louise, the largest, a mile and a quarter long, lies 

 at a height of 5,645 feet above sea-level, and Lakes Mirror and 

 Agnes, overlooking their larger confrere, at heights of 6,500 feet 

 and 6,820 feet respectively. They have been described from the 

 point of view of the explorer and climber by Mr. Walter D. Wilcox, 

 in his interesting and admirably illustrated book " The Canadian 

 Eockies," from which the figures in PL VI are taken. At the end of 

 this work an excellent map of this region is given, and he has also 

 recently published a contour map and detailed study of Lake 

 Louise.* Mr. Wilcox refers to Lake Agnes as being certainly a rock 

 basin, and remarks elsewhere - that only two rock-basin lakes were 

 observed by him, " one of which was a typical cirque lake," no 

 doubt Lake Agnes. This little lake is about a third of a mile long 

 and about 150 yards across, and is surrounded on three sides by 

 mountains. The upper end is a cirque, its terminations culminating 

 in two horn-like peaks. This occupies the upper third of the cliff, 

 the middle third is precipitous rock, the lowest talus. On the left 

 bank the mountain slopes are steep. A peculiar dome-shaped hill, 

 the Beehive, 7,350 feet, and ridge, a continuation of the same, form 

 the right bank of Lake Agnes and overlook the left bank of Lake 

 Louise. The shape of the lake is modified by talus, but there is 

 no possibility of hidden outlet, nor can we find sign of glacial 

 deposits. The opening of this sack-shaped valley, with its tiny lake, 

 is wide, and formed of thickly bedded quartzite. The outflow streara 

 is nearer the left bank of the lake, and the rock floor slopes gently 

 down to it. A shallow groove has been worn away in the quartzite, 

 and the discharge stream empties as a small waterfall into Mirror 

 Lake below. The latter is rather less satisfactory from the 

 geologist's point of view. It is circular in shape and about 

 150 yards in diameter for the most part, no doubt surrounded by 

 live rock, but modified in shape by talus and quite possibly by some 

 glacial deposits. Whether the latter have dammed the exit is 



^ Canada Geol. Surv., 1886, n.s., vol. ii, p. 310. 



^ "A Type of Lake Formation ia Canada" : Jonru. Geol. Chieaao, vol. vii (18991, 

 p. 253. 



