416 GEOLOGICAL SURVEY OF THE TERRITORIES. 



south, for several miles, then left it, gaining the summit of the plateau. 

 On this summit he traveled in a direction generally west, crossing 

 several streams, until he reached a branch of Oebolla Greek, He trav- 

 eled down this branch and the main creek to a point only one mile 

 from its mouth, where the Gunnison is in a tremendous caiion. There 

 he left Gebolla Greek and crossed the ridge to Gedar Greek, a branch of 

 the Uncompahgre Eiver. Thence he followed Gedar Creek and the 

 Uncompabgre to the Gunnison Eiver. He forded the Gunnison at the 

 mouth of Eoubideau's Greek. Thence his course followed a low, 

 trough-like depression in the valley near the mouth of the Gunnison to 

 the Grand Eiver, which he forded about five miles above the mouth of 

 the Gunnison. Below this i)oint his route followed the -course of the 

 Grand quite closely for a long distance below what he supposed to be 

 the mouth of the Dolores, finallj^ crossing to the Green, and theuceto the 

 Sevier, whence it goes nearly north to Salt Lake Gity. The topograph- 

 ical work done by this expedition consists of a narrow belt on each side 

 of their line of travel. The general course of the Gunnison, except in 

 the great canon, was mapped. 



A few months later, Fremont passed over the same route, on his way 

 to California. 



In the summer and fall of 1873, Lieutenant Euffner, United States 

 Engineer Corps, had a party within this district, under the immediate 

 direction of civilian assistant H. G. Prout. This party surveyed the 

 principal part of Ohio Greek, and the head of Anthracite Greek, a 

 branch of the North Fork of the Gunnison Eiver — in all, perhaps, two 

 hundred square miles. His map, of which this area forms but a small 

 portion, was published in the spring of 1874. In Mr. Front's report, 

 which accompanies the maps, he gives certain names to some of the 

 prominent mountain -peaks in this area. These names would be placed 

 on our maps, were it possible to identify the peaks on which they have 

 been bestowed, but neither from his report nor from his map can the 

 names be located. 



GEOGRAPHY OF THE DISTRICT. 



In this report, I shall take up the whole country west of the Sawatch 

 range, over which I have worked during the two seasons of 1873 and 

 1874, in order to consider the Elk Mountains and their spurs as a whole, 

 even at the risk of repeating some of my report on the field-work of 1873. 



West of the Great Sawatch range, the county is drained by the two 

 rivers, the Grand and the Gunnison. The Gunnison is the largest and 

 most important branch of the Grand, while the Grand, by its union with 

 the Green, gives rise' to the Eio Colorado, which drains nearly all of the 

 southwestern part of the United States. 



The principal branches of these rivers are: of the Grand, from the 

 south, Eagle Eiver, Eoaring Fork, Divide Creek, and Plateau Creek ; 

 of the Gunnison Eiver, from the north, Taylor Eiver, Slate Eiver, Ohio 

 Creek, Smith's Fork, and the North Fork of the Gunnison, and from the 

 south, Texas Creek, Cochetopa Greek, Lake Fork, (or Eio delaLaguna 

 of the Spaniards,) Gebolla Greek, and the Uncompahgre Eiver. 



The country between these two large streams, the Grand and Gunni- 

 son, consists, in the eastern part, of the system of mountains known as 

 the Elk Mountains, with its spurs, which, at its western extremity, falls 

 into plateau, considerably broken down by denudation. The Elk Mount- 

 ains, with their spurs, occupy the whole area between the Eagle Eiver 

 aud the portion of the Grand Eiver between the mouths of the Eagle 

 and Eoaiiug Fork on the north, and the Gunnison from its head to the 



