458 



REPORT UNITED STATES GEOLOGICAL SURVEY. 



mit, sketching the topography and correcting it by locations in the usual 

 manner. 



Owing to delays, caused by the neighborhood of hostile Indians, and 

 by bad weather, I was unable to complete the area assigned me. The 

 unfinished portion is in several parts, distributed about the^ western, 

 southern, and eastern borders, the larger part being on the west. Al- 

 together, possibly 500 square miles remain undone. 



The general map of the Park has been plotted on a scale of one mile 

 to an inch, and published on half that scale, *. e., two miles to an inch. 

 The contours are approximately 100 feet apart, vertically. 



During the season one of my assistants, Mr. J. E. Mushbach, was 

 employed in making minute and detailed surveys of the most important 

 groups of springs. From his notes I have made maps of the following 

 groups : 



Name of group. 



Scale of plot. 



Scale of pub- 

 lished map. 



Upper Geyser Basin 



Lower Gey.ser Basin 



Gibbon Geyser Basin . . . 

 Mammoth Hot Springs. 

 Shoshone Geyser Basin. 



Witch Creek Group 



Egeria Springs 



Eustic Geyser Group ... 



Feet per inch. 

 400 

 500 

 200 

 250 

 100 

 500 

 200 



Feet per inch. 

 500 

 800 

 400 

 400 

 500 

 1600 

 266 

 100 



Heights have been determined, as usual, by the cistern barometer, in 

 connection with the vertical circle of the theodolite. Aneroids have 

 been used very little and with the greatest caution, as they have been 

 fonnd to be extremely untrustworthy. 



Barometrical observations have been referred, for computation of 

 heights, to those of the United States Signal Service, at Virginia City, 

 Mont. The height of this station was determined by the computation 

 of a year's coincident 'observations at this point and Salt Lake City, 

 Utah, giving, as a mean result for the former station, a height above 

 Salt Lake City of 1,533 feet. The height of the barometer at Salt Lake 

 City was determined as follows : 



Elevation 

 in feet. 



Ogden track Union Pacific and Central Pacific Railroads, Gardner* 4, 303 



Salt Lake City track, below Ogden track, by the Utah Central Railroad 42 



Salt Lake City track, above sea 4,261 



Signal office. Salt Lake City, cistern of barometer, above track, from levels 



by United States Signal Service 93 



Signal office, Salt Lake City, cistern of barometer, above sea 4, 354 



Hence, Virginia City, signal service office, 1878, above sea 5,887 



The sub-party, under Dr. Peale, was stationary for considerable peri- 

 ods, and, as a full barometrical record was kept by Mr. Mushbach, of 

 that party, I have considered it best to treat the camps of that party as 

 subsidiary hypsometric bases, determining their heights directly from 

 Virginia City, and then using them for the determination of the heights 

 of my more transient camps and stations. The heights of these subsid- 

 iary bases were determined from observations extending over inter- 

 vals from one to three weeks, an interval long enough, particularly as 

 they were quite near Virginia City in height, to establish their eleva- 

 tions with an approach to accuracy. Now, as all these bases are within 

 the small area of the Park, heights determined from them can be sub- 



'Annual Report U. S. Geol. Survey, 1873, p. 658. 



