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GLACIAL STUDII-.S IN CANADIAN UOCKIKS 



455 



extent, a reconstructed glacier. During the hoi daw of the summer 

 these avalanches are of frequent occurrence, crashing into the 

 valley hundreds of feet below with the sound of thunder and the 

 blast of a tornado (fig. 64). In the narrower portion of the valley, 

 known as the " Death Trap," they may shoot completel) across and 

 thus contribute rock fragments to all parts oi the glacier. 



Aberdeen. 



Fig. 65. — Debris covered nose of Victoria glacier. 



2. Frontal Changes. — The Victoria presents an oblique front of 

 nearly one half mile, the general direction of which so nearly corre- 

 sponds with the main axis of the glacier that there is much doubt as 

 to whether we have the actual front or the side (pi. lxi, a). An 

 inspection of the ancient moraines in the valley shows that the 

 front has been gradually swinging around into this position, the 

 ice melting more rapidly upon the western side where less protected 

 by debris. Here for a distance of about 1,600 ft. there is a distinctly 

 stratified ice front, inclined from 7,=,° to 50 and reaching a height 

 ni 75 ft. to 100 ft. T11 midsummer of 1898, there fell from the face 

 of the ice an exceptionally large red quartzite boulder, which was 

 photographed by Prof. C. E. Fay while still in position and a week- 

 later when it had fallen. ( )ne year later the distance of this boulder 

 from the ice front was found by George and William Yaux to be 

 20 ft. : perhaps one-half of this distance being due to recession. In 



