GEOLOGICAL SURVEY OF THE TERRITORIES. 



249 



central layer of pink porphyry. There was evidently a fine fall here at 

 one time, and the valley which comes to the river on the north bank, 

 just below the gate, was then a second channel of the stream. Below, 

 the stream continues deep, with steep banks, gradually widening until 

 it reaches Lewis's Lake.* 



This is a much more regular and symmetrical body of water than 

 Shoshone Lake. It is about two and a half miles long and from one to 

 one and a half miles wide, tapering southward, and is surrounded by 

 mostly gently-sloping shores. These are steepest on the west side, where 

 a few bluffs run out into deep water. Our cauvass-boat being put 

 together, Mr. Adams took a series of soundings, with the results indicated 



upon the accompany- 

 ing sketch, (Fig. 48,) in 

 which the depths are 

 given in fathoms. The 

 deepest part found is 

 seen to be 108 feet, 

 somewhat south of the 

 center of the lake. The 

 deepest sounding yet 

 obtained in Yellow- 

 stone Lake, 300 feet, 

 was made also by Mr. 

 Adams in 1871. 



From our camp at 

 the north end of the 

 lake, the valley of its 

 outlet at the south end 

 lay directly in a line 

 toward the Tetons ; 

 and, early in the morn- 

 ing, before the lake was 

 stirred by the wind, 

 those snow-patched 

 peaks, though forty 

 miles away, were most 

 perfectly reflected by 

 its mirror-like surface. 

 In its setting of the 

 deep-green foliage ot 

 the pine and spruce 

 forests which cover the 

 surrounding slopes, 

 this seems to us one of 

 the most beautiful o. 

 the many fine views 

 seen ux)on our trip. 



Fig. 48. 



* This lake was seen from a distance, in 1871, by Mr. Schonboru, and was located, 

 from his notes, by Mr. Hergesheimer, but its connections were not known. It was also 

 seen on two occasions, and once visited, in the same year, by Captain Barlow; but its 

 connections were wrongly determined, and the lake itself is represented on his map by 

 two bodies of water, some miles apart, and of very different outlines. As it had no 

 name, so far as we could ascertain, we decided to call it Lewis's Lake, in memory of 

 that gallant explorer, Captain Merriwether Lewis. The south fork of the Columbia, 

 which was to have perpetuated his name, has reverted to its Indian title, Shoshone, 

 and is commonly knov/n by that name, or by its translation. Snake River. As this lake 

 lies near tiie head of one of the principal forks of that stream, it may not inapjiropri- 

 ately be called Lewis's Lake. * 



