GEOGRAPHY. 331 



the northward ; two were engaged in topographic and geo- 

 logic work ; and the fourth performed special geologic and 

 photographic duty. All the parties left the Union Pacific 

 Railway, from Point of Rocks and Green River stations, 

 about July 25, and proceeded northward towards the Yellow- 

 stone National Park. 



The primary triangulation party, under charge of Mr. A. 

 D. Wilson, occupied eight of the most important peaks as 

 stations, besides some minor ones. Among the stations were 

 Wind River, Fremont, Grand Teton, and Sawtelle's peaks, 

 near Henry Lake, and several of the more conspicuous points 

 in the Yellowstone Park. 



This is now the most extensive unoccupied area in the 

 West, and, surrounded by great chains of mountains, it has 

 become a resort for hostile bands of Indians, some of whom 

 robbed Mr. Wilson's party of all their animals and a large 

 portion of their outfit, thereby decreasing very materially 

 the work of the season. 



Under the charge of Mr. Henry Gannett, the second divi- 

 sion secured material for a detailed map of the park. This 

 division was divided into two parties, one, with Mr. Gannett 

 as topographer, and Mr. W. H. Holmes as geologist, made the 

 general survey of the park ; while the other, consisting of Dr. 

 A. C. Peale and Mr. J. E. Mushbach, made detailed studies 

 and plans of the geyser and hot-spring localities, with espe- 

 cial reference to the production of an exact model in plas- 

 ter of the whole group. In the survey of the park, forty- 

 seven stations were occupied for secondary triangulation and 

 topography, besides a large number of less importance, stone 

 monuments for future reference being erected on the princi- 

 pal stations. Several groups of hitherto unknown geysers 

 and hot springs were discovered. 



The area of the Yellowstone Park is, in round numbers, 

 3500 square miles. Its surface is in large part level or roll- 

 ing, with several groups and short ranges of mountains di- 

 versifying it. In the eastern part, extending its whole length 

 and forming the water-shed between the Yellowstone and 

 the Bighorn, stand the rugged volcanic peaks of the Yellow- 

 stone range. Nearly all of the park is covered with a dense 

 growth of magnificent pine timber; indeed, west of the 100th 

 meridian there is no area so densely timbered with the ex- 



