GEOLOGICAL SURVEY OF THE TERRITORIES. 69 



side of Green River the same beds incline at an angle of 15° to 20°. 

 The series of beds above described are plainly lower tertiary, and are 

 separated from a succeeding series by a valley about one-fourth of a 

 mile in width. On the border of this valley, some of the upper beds of 

 this first series incline past a perpendicular 45°. This excessive dip is 

 not uncommon among all the stratified rocks in the vicinity of the moun- 

 tain ranges, but I suspect it is confined to the surface, and that some dis- 

 tance in the earth the beds have their normal dip. I was unable to fiud 

 any fossils in this series of beds, nor any indications of coal. Crossing the 

 valley we come to a second series of variegated sandstones, mostly yel- 

 low and rusty brown, standing nearly vertical with the same strike as 

 the first series, and about five miles up Henry's Fork. This interesting 

 valley is filled up with beds which show a perfect conformity. The first 

 bed is a yellow-brown, rather fine-grained sandstone, dipping 75°, a lit- 

 tle west of north. Then comes a series of yellow and light-gray arena- 

 ceous or marly clays, with beds of yellow-brown and light-gray sand- 

 stones projecting somewhat above the surface. Alternating with these 

 layers of sandstone, are quite thick beds of pudding-stone and conglom- 

 erate, composed of rounded pebbles of all the older formations. But 

 what surprised me most were the large masses of purplish sandstones 

 and quartzites, and the carboniferous limestones, sometimes forming the 

 greater portion of thick beds of the conglomerate, four feet in diameter, 

 somewhat worn, evidently derived from the nucleus of the Uinta 

 Mountains. These conglomerate beds are intercalated among the sand- 

 stones through three hundred or four hundred feet in thickness, and 

 are probably of upper eocene age. Above them are at least five hundred 

 feet of sandstones, which have a diminished dip 20° to 30°, and then 

 pass up into the calcareous layers of the middle tertiary or Green River 

 group. We thus see that the aqueous forces that deposited the sedi- 

 ments of the upper eocene beds were brought to bear on the summits of 

 the Uintas, and we can form some conception of the vast period of 

 time they have been subjected to erosion. Since that time all the mid- 

 dle and tertiary beds, comprising many thousands of feet of strata, have 

 been deposited in this region. At the base of this second series of sand- 

 stones is a thin bed of carbonaceous clay, and above and below it are 

 layers of sandstone a foot thick or more, composed almost wholly of 

 Melanias, Paludinas, and Unios, with some reptilian remains. We thus 

 reach a point downward where we can decide that the waters in which 

 these sediments were deposited were purely fresh-water. Green River 

 flows between high vertical walls of these beds, and the opportunity to 

 follow them, step by step in their order of sequence, is excellent. 



We pass gradually up to the Green River beds, where lime forms a 

 large constituent. About two miles north of Henry's Fork the strata 

 become nearly horizontal, and continue so far up Green River toward 

 its source. 



As we pass over the uplands on our way northward toward the railroad, 

 we have on our left hand or west side a long, high, broken ridge of the 

 brown indurated clays of the Bridger group, three hundred to lour hun- 

 dred feet high, which seems at the present time to form the eastern limit 

 of this group. That it continued eastward at one time, perhaps far across 

 Green River, I have no doubt, because remnants of it are seen high up 

 near the banks of Green River ; and on the Big and Little Sandy Creeks, 

 which rise in the Wind River Mountains, are quite extensive develop/ 

 ments of this group, with an abundance of the peculiar vertebrate fos- 

 sils. It is quite possible, also, that the long, high ridges, which so closely 

 resemble them, south of the old stage-road near La Clede and Dug 



