LETTER OF THE GEOLOGIST. XXI 



Geologically speaking, the district was one of singular uniformity. 

 Traveling westward, the older formations reaching back as far as the 

 Triassic, were found. This was followed by Cretaceous, which in turn 

 was covered by Tertiary. About three-quarters of the region surveyed 

 was found to contain beds belonging to this period. Owing to the lith- 

 ological character of the strata, water was a rare luxury in this region, 

 and men and animals were frequently dependent upon looking for springs. 

 Farther west still the Green River group sets in, forming those numer- 

 ous caiions of which that of the White River is one. 



Having completed their work by October 14, the party marched 

 eastward through Middle Park, and after twelve days of rain and snow 

 reached Boulder City, Colo. 



The field-work of the Yampah division during the past season was 

 principally confined to a district of Northeastern Colorado, lying between 

 the Yampah and White Rivers, and between Green River and the sub- 

 ordinate range of mountains that lies west of and parallel with the Park 

 range. The area is embraced between iiarallels 39° 30' and 40° 30', 

 and meridian 107° 30' and lOQo 30'. 



The party consisted of Mr. G. R. Bechler, topographer, directing, ac- 

 companied by Dr. C. A. Yv^hite, the well-known geologist. They pro- 

 ceeded southward from Rawlins Springs, a station on the Union Pacific 

 Railroad, August G, toward their field of labor. From Rawlins Springs 

 to Snake River, a distance of eighty miles, table-lauds form the chief 

 feature of the topography, while from Snake River to the Yampah River 

 the surface is more undulating and thickly covered with sage. Between 

 the Yampah and Wbite Rivers, a distance of fifty miles, the country is 

 mountainous, and on the divide between the Yampah and Wbite Rivers 

 the elevation is 8,000-9,000 feet. Mr. Bechler, after having formed the 

 geodetic connection with the work of previous years, concluded to finish 

 the more mountainous portion of the area assigned to him, which be- 

 gan from a line of meridian with the White River agency, and extended 

 westward to about 108° 10'. Here the party found water and grass in 

 abundance, with one exception. The plateau country, however, was so 

 destitute of water and so cut up with dry gorges or caSons, with scarcely 

 any grass or timber of any kind, that traveling was rendered very diffi- 

 cult. The party therefore made White River its base of supply for 

 water and grass, making side trips into the barren hill-tops or plateaus 

 in every direction. 



From the Ute agency, which is located approximately in latitude 38° 

 58' and longitude 107° 48', the White River takes an almost due west 

 course for 15 or 18 miles, most of the way through an open valley, with 

 here and there narrow gorges. About 50 miles from the agency the 

 river opens into a broad, barren valley, with only here and there scanty 

 patches of vegetation. Soon after the river enters a deep caSon, with 

 vertical walls 2,000 feet or more in height, and continues to increase in 

 depth until the river flows into the Colorado of the West. 



