REPORT UNITED STATES GEOLOGICAL SURVEY. XVII 
the route pursued gave him an opportunity to secure a very accurate 
general knowledge of the geological structure of a large area. The 
Wind River Range proved one of remarkable interest. It has a trend 
about northwest and southeast, with a length of about 100 miles. On 
the west side all the sedimentary belts have been swept away, down to 
the Archean, older than the Wahsatch, and the latter formation rests 
on the Archean rocks all along the base of the range, seldom inclining 
more than 5° to 19°. On the east side of the range the series of sedi- 
mentary formations usually known to occur in the northwest are exposed 
from the Potsdam sandstone, which rests upon the Archean rocks, to the 
Cretaceous inclusive. 
Along thenorthwestern portion of the range the Wahsatch Group only 
is seen for some distance, but as we proceed down the Wind liver 
Valley the formations appear one after the other, until at the lower end 
the entire series is exposed. The Wind River Range may be regarded 
as originally a vast anticlinal, of which one side has been entirely 
denuded of the sedimentary, except the Middle Tertiary. On the same 
side of the range the morainal deposits and glaciated rocks are shown 
on a scale such as we have not known in any other portion of the West. 
Three genuine glaciers were discovered on the east base of Wind River 
and I'rémont Peaks, the first known to exist east of the Pacific coast. 
The morainal deposits are also found on a grand scale in the Snake 
River Valley, on the east side of the Teton Range. The numerous lakes 
have been the beds of glaciers, and the shores of the lakes are walled 
with morainal ridges. North of the Teton Mountains the prevailing 
rocks are of modern volcanic origin, and in the Yellowstone Park the 
hot springs and geysers are the later manifestations of the intense vol- 
canic activity that once existed. All these interesting features were 
studied with care, and the results have been elaborated for the present 
annual report. 
It was with great pleasure that the geologist in charge reviewed the 
ground passed over in 1860, over eighteen years previously. In the 
years 1859 and 1860 he acted as geologist to the exploring expedition 
under the command of Col. William F. Raynolds, nuw of the Engineer 
Corps, U.S.A. A geological map accompanies the report of the expe- 
dition, which embraces Dakota and Montana, with portions of Idaho, 
Wyoming, and Colorado. 
In presenting the final annual report of the field-work of the survey, 
it seems proper to make a brief statement in regard to the causes which 
led to the delay in its publication. During the season of 1878 and 1879, 
Congress passed a law, discontinuing the three surveys then in existence, 
on the 30th of June, 1879, and and establishing the United States Geol- 
ogical Survey. The members of the Geological Survey of the Terri- 
*Geological Report of the Exploration of the Yellowstone and Missouri Rivers, 
under the direction of Capt. (now Lieut. Col. and Brevet Brig. Gen.) W. F. Raynolds, 
Corps of Engineers, 1859-1860. By F. V. Hayden. 
“Sapam i 
