APPENDIX TO REPORT OF THE SECRETARY. 61 



ridge, with a metamorphic and granitic nucleus, which forms a lofty, 

 exceedingly rugged, jagged crest, extending in a north and south direc- 

 tion three-fourths the length of the range, culminating in Mount Hayden. 



In Jackson's Basin, east of the Teton Eange, a vast accumulation of 

 morainal matter was noted. Along the west side of the basin, extensive 

 morainal accumulations occur, which have been cut into beautiful ter- 

 races by Snake Eiver. 



Calcareous tufa, indicating the presence of springs, was found at the 

 mouth of Salt Eiver, in a small basin east of Lincoln Valley, &c. 

 None of these, however, are comparable with the enormous spring de- 

 posits met with at the northeastern foot of the Wind Eiver Mountains, 

 in the upper portion of the Wind Eiver Valley, which were hastily ex- 

 amined late in the season. 



The geological notes given above present only the salient features of 

 the season's work. 



Paleontology. — During the past year the prosecution of paleontological 

 investigation in the field has constituted a prominent feature of the 

 work. This investigation embraces not only a collection and study of 

 the fossil remains, but also the application of such study to the correla- 

 tion of the geological formations that occupy the different districts that 

 have from year to year been surveyed by various parties. Dr. C. A. 

 White, the paleontologist of the survey, has been placed in chage of this 

 branch of the work, which he pursued in the field during the whole of 

 last season. The region studied by him is briefly as follows : That por- 

 tion of the great plain which lies adjacent to the east base of the Eocky 

 Mountains between Cheyenne and a point 25 or 30 miles south of Den- 

 ver ; a portion of Middle Park ; the district drained by Tampa and 

 White Eivers into the Green ; the district which lies adjacent to the 

 southern base of the Uinta range of mountains j that which lies adja- 

 cent to the northern side of those mountains ; a large part of the Green 

 Eiver Basin, and eastward as far as Eawlins Station on the Union 

 Pacific Eailroad. 



The results have been very gratifying; among the more important of 

 ■which is the definition of the paleontological boundaries of certain of the 

 groups of strata, especially those of the Laramie group, over a large area, 

 including both sides of the Eocky Mountains. He has demonstrated 

 the fact that at least the lower portion of the Fort Union group, the 

 Lignitic group of Colorado east of the Eocky Mountains, and the Lara- 

 mie group of King west of those mountains, including the great Bitter 

 Creek series of beds, all belong to one period, and which are included 

 under the general name of Laramie group. 



In the valley of Lake Fork south of the Uinta Mountains, he found 

 the Bridger group well exposed, and in the valley of the Du Chesne, the 

 Green Eiver group. Both these groups have there the peculiar litholog- 

 ical characteristics that distinguish them in the Green Eiver Basin north 

 of the Uintas. 



Important collections of fossils were made by Dr. White, comprising 



