GEOLOGICAL SURVEY OF THE TERRITORIES. 65 



sides or "bad lands," as the surface is usually called. On the summit is 

 a thick bed of conglomerate, composed of the rocks of the mountains, 

 purplish sandstones, quartzites, carboniferous limestones, and quartz. 

 Toward the upper end of the valley this drift conglomerate is one hun- 

 dred and fifty to two hundred feet thick, and becomes thinner as we 

 descend. 



Along the north side of the valley this drift deposit is quite thick all 

 the way down, but it is scarcely seen in the immediate vicinity of the 

 river. The tertiary beds jut up against the sides of the mountains, 

 slightly elevated and inclining 3° to 5°. They were borne up to some 

 extent during the later movements of the internal forces that elevated 

 the mountains. 



On the south side there are remnants of the tertiary beds, apparently 

 perfectly horizontal. I have estimated these modern tertiary deposits 

 to be sis hundred to eight hundred feet in thickness. It is probable 

 that Brown's Hole formed a sort of "bay," into which the waters of the 

 tertiary lake to the west and southwest set up. These modern deposits 

 are not uncommon among the mountain valleys. The Arkansas marls, 

 in the valley of the Arkansas, similar deposits in the Middle Park, in 

 the mountain valleys at the source of the Missouri, in Salt Lake basin, 

 &c, are all, doubtless, of similar character and origin. 



At one point on the north side of the valley, close to the base of the 

 mountains, these beds are weathered into unusually beautiful architec- 

 tural forms, like the ruins of pyramids, &c. They are usually smoothed 

 off on the upper surface into table lands, but this one locality will strike 

 the eye of the traveler at once as a style of weathering of unusual 

 beauty and regularity. There is but little timber along the immediate 

 valley of Green Biver — only a few bitter cottonwoods and willows ; but 

 on the hills there is a thick growth of the low pinon and cedars. In the 

 mountains above, as well as in the valley, there is a universal growth of 

 the sage, {Artemisia tridentata,) grease wood, (Sarcobatus vermicularis , ) 

 and Linosyris. The sage grows to the height of eight and ten feet, and is 

 sometimes six inches in diameter. There were some remarkabte clumps 

 of the Rhus trilobate^ ten to twelve feet high, growing over the Green 

 Eiver bottoms. 



On our return we passed out of Brown's Hole by way of the Henry's 

 Fork road, as it is called in this country, which led us up the caiion of 

 Bed Creek. Here we have the largest display of whitish quartz that I 

 have ever seen in the West. The sides of the caiion rise up eight hundred 

 feet or more, massive quartz. At the entrance, one side of the canon 

 presents the appearance of a cathedral. This style of weathering, for 

 quartz, is unique. There is here an outburst of old trap, and some 

 beds of gneiss. There are also layers of true mica schists. The incli- 

 nation is 60° to 75° northwest. The first quartz, gneiss, and trap that 

 I have seen in connection with the Uinta Mountains occur at Brown's 

 Hole, in this portion of the range. The Bed Creek seems to wind its 

 very tortuous way among the monoclinal rifts for about five miles, where 

 the mountains cease abruptly. 



As we pass up the Bed Canon the sides rise to the height of eight 

 hundred to one thousand feet, composed of white quartz, with a remark- 

 able number of intrusions of trap. The igneous matter has protruded 

 itself into every opening or fissure, in every possible direction, some- 

 times between the strata and sometimes across them, in thin layers or 

 in huge, branching masses. Most of the way for a distance of five miles 

 these high, nearly vertical sides were spotted with the black trap, con- 

 trasting with the white quartz. Nowhere else have I ever seen such 

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