GEOLOGICAL SUKVEY OF THE TERRITORIES. 67 



away, and as I have previously stated, the cretaceous clays jut up 

 against the sides of the quartz ridges. The geology of this portion 

 of the Uinta range is very complicated and interesting. To have solved 

 the problem to my entire satisfaction would have required a week or 

 two. To understand the whole structure clearly my examinations 

 should have been extended to Bear River and beyond. I have no doubt 

 that after a little interval these quartz ridges connect with the range 

 of mountains south of the Vermillion Creek. 



Green River cuts a channel through the eastern end of the Uinta Moun- 

 tains diagonally. At the upper end the unchanged rocks only lie on the 

 east side of the river, but before reaching Brown's Hole the river cuts 

 through the great thickness of the red quartzites. We thus have here a 

 most interesting semi-quaquaversal, on a large scale, including within it 

 several smaller ones. South of Henry's Fork, and east of Green River, 

 the principal ridges incline to the northwest. They gradually flex around 

 until at Red Creek they dip to the northeast, thus forming nearly a 

 semicircle from west to east by way of north. 



Red Creek passes directly through one small semicircle or semi-qua- 

 quaversal, the general dip of which is northeast. Each end bends 

 around so as to jut up against the mountains. At the head of the little 

 branch that flows into Red Creek from the north, between the massive 

 ridges of brown tertiary sandstones and the quartz beds, there is a singular 

 feature, which is an apparent non-conformity — for about four miles up 

 the stream, on the left or east side rising at first one hundred and fifty 

 to two hundred feet, and dipping about 10°. As we approach the head 

 of the bench, this ridge slopes down to the valley and apparently passes 

 beneath the softer beds. At this point commences a series of nearly 

 vertical ridges trending to northwest, and growing thicker and thicker 

 until the lower and middle tertiary ridges are included. The distance 

 between the northern end of the ridge, dipping 10°, and the south end 

 of the same ridge, holding a vertical position, and in some cases passing 

 a vertical 10°, is not more than one hundred yards. There is a similar 

 illustration about five miles up the valley of Henry's Fork. On the north 

 side of the Creek the beds dip at a small angle, while on the opposite 

 side they extend up to the westward, inclining at an angle of 60° to 75°. 



On the high ridges at the head of the little branch of Red Creek, I found 

 in a rusty sandstone impressions of deciduous leaves, among them a Plata- 

 nus ; also a species of poplar, and a Sabal, the same species probably 

 which occurs in the coal-bearing beds near Point of Rocks, on the Union 

 Pacific Railroad. There are also some thin seams of coal here, but the 

 indications of coal are nowhere very marked in the vicinity of this por- 

 tion of Green River. On the east side of Green River, opposite the 

 mouth of Henry's Fork, there is another fine example of a series of semi- 

 circular ridges on" a small scale. At this point all the formations from the 

 quartzite nucleus of the Uinta range, far to the northward until the 

 middle tertiary beds become horizontal, follow each other in perfect order 

 of sequence. The angle of inclination varies much, but the change is so 

 gradual, and the ridges follow each other with such regularity, that no 

 want of conformity can be detected. The geological structure of this 

 portion of the Green River country is very complicated, but interest- 

 ing. I have already shown that members of all the formations of the 

 geological scale, known to exist in this portion of the West, are largely 

 developed here ; that the erosion has been so slight, comparatively, that 

 they are all turned up to the scrutiny of the geologist. 



Before leaving this portion of the country I will say a word in 

 regard to its supposed mineral resources. So far as the physi- 



