796 



GEOLOGICAL SURVEY OF THE TEKRITORIES. 



At Fort Hall I observed through one lunation, obtaining seven cul- 

 minations, which gave the result submitted below, with a possible error 

 of 7.4 seconds. 



The latitude of Fort Ellis, and of all other stations besides Fort Hall, 

 was determined with the sextant, by observations on Polaris and a south 

 star, whenever possible, and on the sun whenever the movements of the 

 party permitted. 



For the determination of the longitude of Fort Ellis, I succeeded in 

 obtaining only two moon culminations. I have adopted the longitude 

 given by chronometer in preference. 



The longitudes of the other stations in the list of astronomical jwsi- 

 tions appended depend on observations with the sextant on the east 

 and west stars, or on the sun, and the rate of the chronometer. This 

 has been exceptionally good, having lost from observations made at 

 Salt Lake City at the beginning and end of the trip, by '2 minutes, 13.05 

 seconds, between May 28 and October 29. Its rate was checked during 

 the season by returning to Fort Ellis, the Three Forks of the Missouri, 

 and Fort Hall, and, in all cases, was found to be very uniform. • 



YELLOWSTONE DIVISION. 



List of astronomical positions. 



Fort Hall, Idaho, 



VirgiuiaCity, Mont., (United States signal-service office) 



Fort Ellis, Mont., (camp 1) 



Helena, Mont., (surveyor-general's office) 



Camp 3 



Camp 4, Bottler's Ranch 



Camp 



Camp 6 



Month of Gardiner's River, northern boundary of Yellow- 

 stone National Park 



White Monntaiu Hot Springs, (camp 7) 



Camp 8 



Camp 9 



Yellowstone Falls, (camp 11 ) 



Camp 12 



Head of Yellowstone River, at lake 



Camp 13 



Lower Geyser Basin, (camp 14) 



Camp 15 



Camp 16 



Camp 17 



Camp 18 



Camp 19 



Camp 21 



Camp 22 



Camp 25 



Three Forks of the Missouri, (camp 27) 



Camp 28 



Camp 35 



Camp 36 



Camp 39 



Camp 41 



Camp 42 



Camp 43 



Camp 44 



Western boundary of Yellowstone National Park 



Southern boinulaiy of Yellowstone Nat'i Park, (approx). 

 Eastern boundary of Yellowstone Nat'l Park, (approx).. 



44 9 30 



HI 14 3C 



110 



