50 



GEOLOGICAL SURVEY OF THE TERRITORIES. 



observations were made by different members of the party, and some 

 additional facts were obtained by Br. Peale. These will all appear in 

 subsequent portions of tliis report. We will, tlierefore, pass by the won- 

 derful basaltic columns, which are so finely shown in Fig. 9. Tower Falls, 



Fig. g. 



*■* 



^A 





h*'*- 



Grand Canon, Upper 

 and Lower Falls of the 

 Yellowstone, as well as 

 <he numerous groups 

 ("f hot springs, which 

 are abundant, can only 

 be alluded to in gen- 

 eral terms. Some new 

 groups of springs were 

 added to the list, but 

 none that threw any 

 additional light on 

 their history. There 

 are, no doubt, many 

 small groups of springs 

 yet undiscovered. 

 Glowing accounts 

 were given to us of a 

 very interesting group 

 at the very source of 

 the West Branch of 

 Gardiner's River. 

 When the National 

 Park has been ren- 

 dered more easily ac- 

 cessible for travelers, 

 many curious discov- 

 eries will, no doubt, 

 be made which will in- 

 crease the public in- 

 terest in this wonder- 

 ful region. The origin 

 of the remarkable 

 * lake-basin, in which 

 the greater part of the 

 il wonders is located, is 

 most interesting in a 

 geological point of 

 view. I am convinced' 

 that it is not altogether 

 one of erosion, but in part of elevation. It seems probable, however, that 

 the intense volcanic action, of which Ave see everywhere such unmistak- 

 able indications, occurred at a very modern geological period, not further 

 back than the Pliocene period, and perhaps even not lat^r than what 

 we usually denominate the Quaternary or Drift. At any rate, it is 

 probable that the waters surrounded and perhaps covered the highest 

 mountain-peaks, inasmuch as we not only find drift-bowlders upon 

 most of the loftiest ranges, but the volcanic conglomerates, tuffs, &c., 

 are arranged in a stratified and, for the most part, horizontal position^ 

 as high as the most elevated peaks in the Yellowstone Basin. On. the: 

 west side of the lake some of the highest peaks, as Pomeroy, Langford,, 

 Stevenson, Doane, and others, are seemingly huge-volcanic cones, com- 





I luul killJ I 



BASALTIC COLUMNS, \ ELLOW STONE, NEAR MOUTH TOWER CREEK. 



