104 GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



thin, corresponding to the average lighter snowfall above reported for these 

 years. 



A still further confirmation of the conclusion reached above, that from the 

 middle of the year 1898 there has been a marked increase in the sno\vfall, is 

 furnished by the notes and photographs of the Messrs. Vaux, to be noted later. 

 Their photograph of 1898 shows a large amount of rock exposed along the slopes 

 of Leda, Pollux, and Castor, as well as between the eastern and middle ice streams. 

 In 1899 they note that the n^ve line is lower and the hanging glaciers are much more 

 active, giving rise to frequent avalanches, which were very infrequent in 1898. 

 When their photograph of 1898, reproduced here as plate xli, figure 2, is com- 

 pared with that of the Detroit Publishing Co., taken in 1902 (plate xxxix, figure 

 i), the increase in the amount oinev6 is striking, the presence of the bergschrunds, 

 in areas that were bare rock, indicating that glaciers had fonned in the meantime 

 and that there is not simply a covering of loose snow, such as might fall in a 

 night. In looking over the broad snow expanse one does not think of there being 

 hanging glaciers upon the slopes of Castor and Polliix, as they seem to blend with 

 and be an integral part of the general n6v6 field. In 1898 they were separated 

 sufficiently so that it was natural to think of them as being detached. In two 

 weeks of August, camping in plain sight of the region, in 1904 and 1905 , the writer 

 does not remember to have seen or heard a single avalanche from this quarter. 

 They were frequent in the smnmer of 1899, and, presumably, continued so un- 

 til the space between the lower neve and the upper became so filled in as to 

 prevent further slides. From all the evidence obtainable it seems most prob- 

 able that the major stratification planes in the Asulkan n^v^ represent the breaks 

 between the successive year's snowfall, and that a phase of deficient precipita- 

 tion closed in this region about the middle of the year 1898, since which time 

 the average annual precipitation has been in excess of the normal. 



The disturbance of the ice noted upon the eastern stream does not destroy 

 the stratification, since it extends only part Avay across the stream and is not 

 intense. The strata are, however, more or less tilted and distorted. The lower 

 stratum is wedge-shaped, having apparently lost from its basal portion by sub- 

 glacial melting. The blue bands in this strattim are not parallel with its upper 

 surface, but cut it at angles of about 13° to 14°, being more nearly parallel with 

 the valley floor. In the stratum just above, the blue bands and stratification 

 planes were conformable. In general, the blue bands were found to be regularly 

 developed, quite in contrast with the stratification. The dirt stripes showed 

 well over the surface and margins of the eastern stream, some excessively thin 

 ones being observed and previously noted (page 54). About the nose, upon the 

 walls of some of the longitudinal crevasses, the blue bands were found to dip 

 back into the glacier at angles of 11° to 28°. About the eastern side they were 

 found to dip downwards and inwards, nine observations giving an average of 

 46°, with a range from 36° to 57°. The granules about the nose are small, 

 compared with those seen in the larger glaciers, and will average less than a 

 half-inch in diameter. 



