REPORT OF ORESTES ST. JOHN. 
LETTER OF TRANSMITTAL. 
OFFICE UNITED STATES GEOLOGICAL AND 
GEOGRAPHICAL SURVEY OF THE TERRITORIES, 
Washington, D. C., September, 1879. 
Sir: [submit herewith my reporton the geology of ine district assigned 
to the Wind Riwer division of the survey during the season 1878, together 
with a copy of the map of the territory visited by myself during the 
seasons 1877 and 1878, on which the distribution of the geological form- 
ations is indicated by appropriate colors. 
The party to which I was assigned as geologist the past season was 
in charge of Mr. Frederick C. Clark, topographer, accompanied by Mr. 
Nelson Perry, mineralogist, Mr. Wells, topographical assistant, George 
and Mae, packers, and the cook, Henry. Outfitting at Cheyenne, the 
party was transported by rail to Granger Station on the Union Pacific 
Railway, whence in company with Messrs. Gannett and Peale’s party 
we moved up the valley of the Green River, arriving on the southern 
confines of our territory on the 31st July. 
The first work performed was in the northern extremity of the Wyoming 
Mountains, in the southwest corner of the district. We thence moved 
along the southern foot of the Gros Ventre Range to the west flank of 
the Wind River Mountains. Later in the season the northern half of 
the eastern slope of this range was visited, the work extending to a 
rapid survey of the eastern portion of the Gros Ventre Basin, over to 
Buffalo Fork. In the latter quarter, about the middle of October, just 
as we reached Pacific Creek, a heavy fall of snow virtually closed the 
season’s field-work. The return was via Togwotee Pass, where the snow 
lay to the depth of above a foot, descending Wind River to Camp Brown, 
from which place I returned by stage to Green River Station, on the 
Union Pacific Railway. The time actually spent in the field was about 
ten weeks, during which time ur movements were harassed by inclem- 
ent weather, and latterly by that peculiar mental condition consequent 
on the uncertain and exaggerated rumors relative to the movements of 
hostile Bannacks by whom the country was said to be overrun, but of 
whose presence we saw no more than the traces of some days’ old trails. 
In relation to the geological map, a copy of which is herewith trans- 
mitted, so far as it records actual examinations it is believed to be in 
the main correct. But it embraces tracts which were either not visited, 
the geological features being viewed at a. distance, or other sections 
where the data derived in the course of a hasty visit failed to afford the 
means of determining the exact age of the rock formations found therein. 
In the former case is included the belt traversing the central portion of 
the Snake River Mountains ,whose rather complicated g geological struct- 
ure it was impossible to satisfactorily make out from such examina- 
tions at a distance, with which we had to be content; and in the latter 
inistance are included the several areas indicated by the common color 
173 
