XX REPORT UNITED STATES GEOLOGICAL SURVEY. 



daily iu the winter season, must be well stocked with game. It seems 

 well adapted to its present use as an Indian reservation, and is likely to 

 remain for years to come more valuable for the Indians than it could 

 be for settlement. 



In the far western portion, and outside the limits of the reservation, 

 one large vein of asphaltum and several small veins were found, and also 

 running springs of the same material, all of which, if once reached by 

 railroads, will prove of great commercial value. These deposits have 

 been spoken of before, but their location has not been accurately de- 

 termined. The principal vein seen by this party is at present about one 

 hundred miles from railroad communication, but less than half that dis- 

 tance from white settlement, and is likely in the present rapid growth 

 of that country to be within a few years made available. 



According to the report of F. M. Endlich, the geology of this district is 

 very simple, though interesting. Inasmuch as but one divide of impor- 

 tance occurred within the district, the work was somewhat simplified. 

 This was formed by the Book Cliffs, between the drainages of the Grand 

 on the south and the White on the north. Both these rivers flow, a lit- 

 tle south of west, into Green Eiver, which they join in Utah. From the 

 junction of the Grand and Green downward the river is called the Great 

 Colorado. Orographically, the region surveyed is comparatively sim- 

 ple. The Book Cliffs are the summit of a plateau about 8,000 feet above 

 sea-level, continuing unbroken over to the Green Eiver. Toward the 

 south these cliffs fall off very steeply, forming deep caiions that contain 

 tributaries of the Grand Eiver. On the north side, with the dip of the 

 strata, the slope is more gentle, although, in consequence of erosion, 

 numerous precipitous cliffs are found. Descending in that direction, the 

 character of the country changes. Instead of an unbroken slope, we 

 find that the plateau has been cut parallel by the White Eiver drainage, 

 and the long, characteristic mesas of that region testify to the action of 

 erosion. Approaching the river, constantly descending with the slight 

 dip of the strata, the bluffs become lower and lower. Though the creek- 

 valleys are wide, and at certain seasons no doubt well watered, the veg- 

 etation is that of an arid country. Dwarf pines, piiions, and sage-brush 

 abound, to the almost entire exclusion of other trees or grass. Travel- 

 ing down White Eiver, this character is again found to change. A new 

 series of bluffs, occasioned by heavy, superincumbent strata, gives rise 

 to the formation of deep caiions. For forty-five miles the party followed 

 the caQon of the White, that, no doubt, is analogous to that of the Green, 

 and probably closely resembles that of the Colorado in its detail features. 

 Vertical walls inclose the narrow river-bottoms, and the slopes of the 

 higher portions are ornamented by thousands of curiously-eroded rocks. 

 "Monuments" of all kinds, and figures that can readily be compared 

 to those of animated beings, enliven the scenery, which otherwise would 

 be very monotonous; 2,000-3,000 feet may be stated as the height of the 

 walls inclosing the White Eiver. 



