GEOGRAPHICAL FIELDWORK OF THE YELLOWSTONE PARK 



DIVISION. 



By Henry Gannett, E. M. 



LETTER OF TRANSMITTAL, 



Washington, D. C, September 26, 1881. 

 Sir : I have the honor to transmit herewith my report on the field- 

 work of the Yellowstone Park Division, United States Geological Survey 

 of the Territories, during the season of 1878. 

 Yery respectfully yours, 



HENEY GANNETT. 

 Dr. F. V. Hayden. 



ITINERARY. 



In accordance with instructions, the Yellowstone' Park Division 

 started for its field of labor on July 26, 1878, taking the field at Granger 

 Station, Wyoming, on the Union Pacific Eailroad. 



At the outset the party comprised, besides myself, Dr. A. O. Peale, 

 geologist; J. E. Mushbach and Russell West, assistant topographers ; 

 with two packers and a cook. After entering the field of work, Messrs. 

 Peale and Mushbach were detached for special work in connection with 

 the hot springs and geysers, while Mr. W. H. Holmes joined my party 

 as geologist. 



The route of the party to the field of work lay up the Green River 

 Basin, following in a general way the course of Green Riper. At the 

 mouth of Lead Creek we left the Green on our right and swfuck over in 

 a northwesterly direction to the drainage basin of Hoback's River, a 

 large left-hand branch of Snake River. This stream heads in the east- 

 ern slopes of the Wyoming Range, and in the southwestern slopes of the 

 Gros Ventres Mountains, and, having accumulated its waters in a basin 

 in the angle of these two ranges, it cuts a tremendous gorge through 

 the former on its way to join the Snake. This canon has been very 

 much used by the Gros Ventres, Bannock, and Shoshone Indians as a 



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