34 GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



year this would indicate an advance, whereas the glacier was actually in retreat. 

 The necessity of taking the measurements as nearly as possible at the same cor- 

 responding time in the season becomes evident. In 1904 measurements were also 

 made August 4 and September 13, giving distances of 76 and 86.45 feet respect- 

 ively. If we assume a uniform recession between these last two dates we have 

 a daily amount of 0.26 feet and for the interval between August 4 and August 23, 

 at which date the measurement was made in 1903, an additional recession of 4.94 

 feet. This amount, added to that of August 4, gives 80.94 feet, and the approxi- 

 mate recession from August 23, 1903, to August 23, 1904, was 5 feet. In 1905 the 

 measurements were made September 2, and gave a distance of 106.8 feet from 

 the reference block to the ice foot. This means a recession of about 25 feet for 

 the year 1904-5. For the series of six years 1899 to 1905 the total amotmt of 

 recession observed at this point was 86.8 feet, or an average of 14.5 feet annually. 

 The following summary for this boulder may be given: 



1898. Fell from ice early in August. 



1899. 20 feet from ice foot. 

 1 899-1 900. Ice receded 6 feet. 

 1900-1903. Average recession of 19 feet. 

 1 903-1 904. Ice receded 5 feet. 



1 904-1 905. Ice receded 25 feet. 

 1899 to 1905. Average recession 14.5 feet. 



About 375 feet nearer the nose a second block was selected for reference and 

 upon July 23, 1904, marked "B. To ice 38.5 ft. 7/23/04. Sr." Between this 

 date and August 4, 1904, the recession amounted to 3.9 feet and up to September 

 13 equalled 11.5 feet. The distance from the block to the ice foot was again 

 measured September 2, 1905, and amounted to 63.2 feet, indicating a recession 

 between September 13, 1904, and the latter date of 24.7 feet. Calculated, as 

 above, for the year September 2, 1904, to September 2, 1905, the recession was 

 approximately 15 feet. Since the exposure of the ice face opposite blocks A and 

 B is so nearh" uniform, we may assume safely that the rate of melting upon the 

 oblique face is substantialh' the same at the two points of reference. The 

 diminished recession of the ice at B would then indicate that the forward move- 

 ment of the layers here must be greater than at A. From data already cited 

 it is seen that the forward movement at the nose is insignificant and it appears 

 that the main current of ice, as it approaches the nose, is deflected to the west- 

 ward and that the oblique ice wall is in reality part of the front. 



c. Shearing. The steeply inclined ice front, having a slope of 46°, near 

 reference block B, shows a succession of ice strata, more or less well defined, which 

 dip back into the glacier at a rather steep angle. At the mouth of the abandoned 

 drainage tunnel (plate viii, figure 4, and plate xii, figure 3), these strata in 1904 

 had a dip of 26°, which is below the actual dip. Between these strata there is dust, 

 sand, a little fine gravel, and, occasionally, a cobble-stone, but the amount of for- 

 eign matter is small and inconspicuous. A few consecutive days' visits to this 



