90 



GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



tarred a number of boulders in closest proximity to the margin, which rocks 

 could still be indentified in 1905. (See rocks marked T, plate xxxi.) 



In 1899 George and William Vaux set a line of 8 steel plates across the glacier, 

 some 1,400 to 1,500 feet back from the nose, their line lying somewhat obliquely 

 to the main axis of the glacier (see map). The average surface slope was given 

 as 22°, and the distance across the glacier along the line of plates was 1,720 feet. 

 A base line was laid out along the higher portion of the right lateral moraine, 

 229.5 feet in length, and the plates located by triangulation, July 31, 1899. Bear- 

 ings were taken t;pon the plates August ii,;t899,and Septembers, 1899, the lat- 

 ter work being done by iVIessrs. H. B. Muckleston and C. E. Cartwright, of 

 the Canadian Pacific Railway. One year later (August 6, 1900) the plates were 

 again located by the Messrs. Vaux and their forward movement for the 372 

 days determined. The following table is based upon their data published in 

 Appalachia, vol. ix, 1900, p. 160, and the Proceedings of the Academy of Natural 

 Sciences of Philadelphia, March, 1901, p. 215. 



TABLE VII, 



Observations upon the Line of Steel Plates set across the 

 Illecillewaet Glacier, July 31, 1899. 



(Total Distance across Glacier along Line of Plates 1,720 feet.) 



An inspection of the above table shows that the maximum movement, for 

 both the summer and the entire year, lies well to the west of the axis of the 

 glacier. The greatest average [daily movement was made by plate 6, which 

 lies 1 20 feet to the west of the center, while plates 7 and 8 show only slighth- less 

 movement. This is in harmony with what is known concerning the flow of 

 glaciers on a curve, the maximum movement taking place not at the center, 

 as in the case of the very straight Victoria, but lying between the center and tlie 

 convex Side. The average daily movement of plate 6 for the year is 94 per cent 

 of its summer motion, as compared with 81 j^er cent for the corresponding ]ilate 

 upon the Victoria. For some reason, not easily explained from the data at hand 



