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SMITHSONIAN MISCELLANEOUS COLLECTIONS 



[vol. 47 



issues at a point between the nose and the oblique ice front, cascad- 

 ing over the rocks of the lately formed moraine. At times during 

 the summer there is more or less discharge from here up as far as 

 the reference boulder. Formerly the main discharge was through 

 a tunnel, now clogged with frozen ground moraine, the mouth of 

 which is shown in pi. lxi, a. The opening is 12 by 7 ft. at the lower 

 end and extends obliquely backward under the ice for a distance of 

 160 ft. The fluted walls and ceiling show that it was at times com- 

 pletely filled with torrential waters ( fig. 67). The temperature of the 



Fig. 67. — Abandoned drainage tunnel. Victoria glacier. 



water from the main exit varies from 32 to 33 F., rendered some- 

 what higher, undoubtedly, by the marginal stream. During the late 

 spring and early summer the melting snows upon the mountain 

 slopes contribute considerable wanner water to the glacial brook 

 which empties into Lake Louise, but only immediately after rains 

 do these side streams supply an appreciable amount of sediment. 

 For a distance of some 600 ft. there has been built out into the lake 

 a low delta of sand and gravel, the material for which, in the main, 

 has come from beneath the glaciers which occupy the head of the 

 valley. Determinations of the amount of sediment and volume of 



