GEOGRAPHY OF NORTH AMERICA. 207 



The southeast, or Sweetwater division, as it was called, 

 embraced an area of nearly 11,000 square miles, extending 

 northward to 41 45' K lat,, and westward to 109 30' W. 

 long. In working this area, one hundred and seventy-one 

 principal topographical stations were occupied, besides twen- 

 ty or more subsidiary stations; eighty or more stone monu- 

 ments were erected. While many of these stations, owing 

 to the extremely desolate and irreclaimable character of 

 the country surveyed, will probably never be used as initial 

 points for detailed surveys, there still remain many others, 

 which will be of great value as starting-points for isolated 

 pieces of rectilinear work, where fertile valleys and oases in 

 the desert country are rapidly coming into demand by set- 

 tlers. The most important of these fertile valleys lie in the 

 mountainous region to the north, in the upper waters of trib- 

 utaries of the Platte and Yellowstone ; and into this district a 

 rectilinear survey was pushed by measuring a guide-meridian 

 from the railway north, and the establishment of base-lines 

 within the region itself. The sniide-nieridian had to be meas- 



CD CD 



ured over seventy-five miles of desert country, where water 

 was extremely scarce. Owing to threatened danger from 

 hostile Indians, who were known to be in the vicinity of the 

 Big Horn Mountains, the party was obliged to leave in the 

 northeast about eight hundred square miles of unexplored 

 territory. 



The southwest, or Green River division, was a rectangle of 

 similar size to the last, but the surveying party extended its 

 work a little beyond its western limits, so that 12,000 to 13,000 

 square miles were surveyed. This area contains a greater 

 extent of hilly country, but none so elevated as that in the 

 northern portion of the Sweetwater district; and in it nearly 

 three hundred and fifty stations and locations were made, 

 more than fifty of which were marked with stone monuments. 

 The party found the Green River basin a broad, flat, almost 

 unbroken expanse, covered mainly with sage-brush and scat- 

 tered bunch-2;rass, but the bottom lands well grassed and 



CD * CD 



wooded. In the broken country to the west, the more ele- 

 vated portions were heavily timbered, the hilly parts grass- 

 covered, and the valleys filled with good soil, easily irri- 

 gable. 



The Teton division to the north extended to the borders 



