78 GLACIERS OF THE CANADIAN ROCKIES AND SELKIRKS. 



d.6bris is carried and rolled down the valley. The channel beds are lined with 

 coarse rounded boulders, making the fording of the stream, afoot or mounted, 

 somewhat difficult, especially after a day of rapid melting. In the early moming 

 the volume and velocity are somewhat reduced. 



The dilution of the Yoho drainage, with that from the adjoining valleys, 

 raises the temperature, as was noted in the case of the Wenkchemna drainage 

 brook. The last two weeks of August the temperature ranged from 33.8° F. to 

 35.2° and gave an average of 34.7°. Opposite the Takakkaw Falls, about five 

 miles from the nose, the stream has descended 770 feet and its August temperature 

 has been raised from three to four degi-ees. At Field the temperature of the 

 Kicking Horse, August 23, 1904, was found to be 44.2° F. at 5:15 p. M. On 

 August 30, 1905, at 6:30 A. M. it was 39.6°. 



8. Frontal Changes. 



In August, 1 90 1, reference marks about the nose of the Yoho were indepen- 

 dently established bv Miss Vaux and Mr. H. W. Du Bois, from which it was deter- 

 mined in 1904 that the glacier had receded, in the three years, a distance of iii 

 feet (August 16, 1901 to August 18, 1904), or at the average rate of 37 feet a 

 year. Measured to the block of ice which had until very recently constituted 

 the nose, the distance was 92.1 feet, of which 23 feet was for the year 1903-4, 

 reducing the average to about 31 feet for the three years. Between August 18, 

 1904, and August 31, 1905, the retreat was found to have been but 9 feet. The 

 average annual retreat for the four years 1901 to 1905 has been 30 feet. At a 

 second station upon the western side of the drainage stream the retreat from 

 August 17, 1904, to August 31, 1905, was 4.6 feet. From these meager data 

 it seems that the Yoho is having its retreat checked. 



9. Former Activity. 



a. Moraines. Lack of time prevented any careful survey of the entire Yoho 

 Valley from the glacier to where the valley joins that of the main Kicking Horse. 

 No coarse moraines of the type described for the Victoria and Wenkchemna 

 were seen and their absence is easily accounted for by noting the absence of steep 

 cliffs about theglacier and its neve fields, plate xxviii, figure 2. In passing up the 

 valley the trail crosses two steep ridges, densely covered with vegetation, but 

 these appear to be of the nature of mountain spurs, or rock slides, from the 

 western side of the valley. About i ,000 feet from the present nose there is an 

 interesting display of modified ground moraine, lying mainly upon the eastern 

 side of the stream (plate xxviii, figure i). The structures consist of low 

 knolls and crescentic ridges, connected with the weak lateral moraines by faint 

 ridges. Six series may be made out, concentrically placed and with their con- 

 vexities directed down stream, diminishing in height and distinctness toward 

 the glacier. The ridges vary in height from one to twelve feet, the longest 

 being in the form of a semicircumference with a radius of twenty feet. The 

 ridges possess the smooth, rounded outlines of drumlins, but lack their profile 



