PREFACE. % V 



In 1874, I started with a pack train from Green River Station, went up 

 Little Bitter Creek, across Quien Hornet Mountain, through Red Creek 

 Canon into Brown's Park; thence southeastward to the junction of the Snake 

 River with the Yarnpa, where it was crossed; thence across the Yampa 

 Plateau to the foot of Split Mountain Canon, and thence to the Uinta Val- 

 ley. Returning from the Uinta Valley I visited the region drained by 

 Ashley's Fork and Brush Creek, crossed the Uinta Mountains to the head 

 of Sheep Creek, and returned to Green River Station. 



The course thus marked down was that followed by the pack train, 

 which moved but slowly, usually resting two days out of three, while my 

 own line of travel was in diverse directions from this general route. 



In 1875, I again started with a pack train from Green River Station, 

 went east to Rock Springs and Salt Wells, thence south to the mouth of the 

 Vermilion, thence to the eastern foot- of the Dry Mountains, thence west 

 through Brown's Park, past Flaming Gorge to the head of Sheep Creek, 

 and thence through the Cameo Mountains to Green River Station. On this 

 trip also the train moved slowly, and my studies were extended many miles 

 in either direction from the general route. 



A few days later I made a trip to Salt "Wells and Bitter Creek Stations, 

 and particularly examined the region about Black Butte. 



The last part of the descriptive geology has been greatly condensed ; 

 this is especially the case with the description of the structure of the Yampa 

 Plateau, Junction Mountain, Diamond Peak, the Dry Mountains, Brown's 

 Park, and the Aspen Mountain district. It was intended to illustrate the 

 structural characteristics of these regions with a series of diagrams and sec- 

 tions, but the plan was abandoned because the appropriation was exhausted. 

 It was intended also to prepare a chapter on the physical features of the 

 region, treating of the mountains, plateaus, monoclinal ridges, hills, parks, 

 bad-lands, and alcove lands, and further treating of the three great kinds of 

 drainage found in the region, viz, antecedent, consequent, and superimposed; 

 but the necessity for immediate publication Avas so great that this plan has 

 also been abandoned, and to this subject I hope to recur at a future time. 



On my travels during the year 1875, Prof. C. A. White was my geo- 



