264 



GEOLOGICAL SURVEY OF THE TEREITORIES. 



outlet ; and it appears not improbable that the glacier did split, as sug- 

 gested, during at least a part of its existence, and liow out at this end as 

 well as at the southern one. These waters come so near together that, 

 without any connected esaminations, and without recognition of the 



rise of 144 feet from Jackson's Lake 

 to Leigh's Lake, water-communication 

 between the two had been inferred 

 and reported ; and Mr. Adams at- 

 tempted to find a passage across in 

 his canoe, but, failing in that, was 

 obliged to make the long detour by the 

 true outlet of Jackson's Lake. 



About a mile south of Leigh's Lake, 

 another, of about the same size, which 

 we have called Jennie's Lake, after 

 Mrs. Leigh, lies in the mouth of the 

 Great Canon of the Teton Eange. 

 Passing up this canon for a short dis- 

 tance, Mr. Taggart found a cluster of 

 falls and rapids about 250 feet high, 

 with lofty, ijrecipitous walls on either 

 hand, which jirevent ready access to 

 the upper part of the caijon, which 

 winds around to the western side of 

 the peaks, where its lofty walls were 

 seen by us in July. This canon 

 gathers the entire drainage of the 

 western side of the three principal 

 peaks, so long known as the Three 

 Tetons. The water of these mountain- 

 streams is so pure as to make it cer- 

 tain that not the least glacial erosion 

 is now going on. at any point on the 

 range. Though many schists occur 

 in the mountains, very few of them 

 have contributed to the terminal mor- 

 aines, nearly everything except the 

 granites having been ground or 

 weathered fine during the downward 

 passage. The moraines about Jennie's 

 Lake are not very largely developed ; 

 possibly, the more abundant flow of 

 water from beneath this glacier, con- 

 sequent ui)on the greater size of its 

 basin, washed away the debris from 

 here more thoroughly than was done 

 elsewhere. At two other caiions, far- 

 ther south, similar lakes occur. The 

 more northern of the two, which we 

 have called Taggart's Lake, is sur- 

 rounded by five concentric moraines, 

 the elevations of which above the old 

 river-channel, which ijasses just out- 

 side of them, were taken by Mr: Tag- 

 gart. as follows : The outer one, 162^ 

 feet; second, 206 feet; third, 271 feet; 

 fourth, 316 feet; filth, 422 feet. The 



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