X REPOET UNITED STATES GEOLOGICAL SURVEY. 



another base-line was measured and connected with the work as brought 

 forward from the Eawlins base. 



After occupying- Mount Preuss, Soda, Paris, and North Logan Peaks, 

 the party marched to Evanston, where connection was effected with the 

 astronomical station made at this point by the boundary survey of Wyo- 

 ming. Stations were also made on Medicine Butte and Ogden Peak, 

 thus connecting with the primary triangulation of the fortieth parallel 

 survey. From Evanston the party moved eastward, occupying Pilot 

 and Black Buttes, again visiting Separation Peak near Eawlins, thus 

 bringing the work back to the point of beginning, where the party was 

 disbanded and the train sent into winter quarters at Cheyenne. 



Mr. Wilson has finished the preliminary computations of his work, and 

 a chart showing the results has been published. Twenty-six points 

 were occupied, while many others were located by foresights, among 

 them the Grand Teton and Washakie Needles. 



The triangulation covered an area of about 28,000 square miles, extend- 

 ing from longitude 107° to 112° and between north latitude 41° 10' and 

 43° 50'. 



Stone monuments were built on all occupied points for future refer- 

 ence, and when the final computations are made, the latitude and longi- 

 tude of all these points will be given, with azimuths and distances 

 between the points. 



TOPOGRAPHY. 



The topographical field-work of the past season was carried on by 

 three parties, to each of which a definite area was assigned to be sur- 

 veyed. These areas were approximately in the form of rectangles, 

 limited by meridians and parallels of latitude. Each of them contained 

 about 11,000 square miles. That assigDed to the Teton division, in 

 charge of Mr. G-. E. Bechler, lay between the meridians of 109° 30' and 

 112 G and the parallels 43° and 44° 15'. This area comprises nearly all 

 the country about the sources of Snake Eiver, including the very rug- 

 ged range of the Teton Mountains and the northern half of the Wind 

 Eiver Mountains. From the character of the country, being nearly all 

 mountainous, and much obstructed by living and fallen timber, work 

 was necessarily slow, yet Mr. Bechler succeeded in surveying nearly 

 6,000 square miles up to the early part of September, when he was obliged 

 to stop work and leave the country, owing to the proximity of Joseph's 

 band of hostile Indians. About one- third of the area surveyed by this 

 division lies south of the Snake and west of Salt Eiver. The remainder 

 includes the greater part of the most rugged mountains, among them 

 the T6tons and a portion of the Wind Eiver Eange. 



That portion of the district lying south of Snake Eiver consists of the 

 northern ends of two mountain-ranges, known as the Blackfoot and 

 Caribou Eanges, with their adjacent valleys. These ranges have the 

 normal trend ; are here scarcely high enough (6,000 to 8,000 feet above 



