GEEEN EIVER EOCENE. 243 



Insoluble residue : 



Silica. 23.47 



Alumina 5.40 



Lime . . . . . : 0.26 



Magnesia 0.06 



29.19 



The dip of the beds, as seen to the east of Green River City, in the 

 line of blujEFs to the north of Bitter Creek, is very regular at an angle of 4° to 

 the westward. They are also exposed at the base of the bluffs, and in the 

 ravines on the western side of the river opposite Green River City, where 

 they preserve the same angle, but at the summits of the low flat ridges 

 between Green River and Black's Fork are covered by thin-bedded drab 

 sandstones, which form the base of the Bridger group, in general too much 

 disintegrated to show distinct planes of bedding, but apparently dipping not 

 more than 1° or 2° to the westward. The formation descends slightly to 

 the northward, and the most northerly point, where a good exposure of the 

 shale beds was found to the west of the river, is in the railroad-cut 4 miles 

 west of Green River City. To the north of this point, the upper brown 

 sandstone can be traced along the west bank of the river to a point about 

 12 miles above Green River City, where it crosses the river and disappears 

 to the northward beneath the lower beds of the Bridger group. 



Six miles south of the railroad, Green River enters a canon-like gorge, 

 cut through the lower beds of this formation, which was not explored by our 

 parties. From this point south to the lower valley of Henry's Fork, the beds 

 of the Green River series preserve a general inclination of 4° to 5° to the 

 westward, forming flat mesa-ridges, which rise in a series of terraces from the 

 Green River to the meridian of Quien Hornet Mountain, and a short distance 

 to the west of the river are covered by the ■ horizontal beds of the Bridger 

 group. Along the flanks of the Uinta Range, they have locally steep dips 

 to the north. On the northern face of Quien Hornet Mountain, as we 

 have seen, the buJff calcareous sandstones of the lower portion of the series 

 are exposed, dipping 4° to the northward, overlaid non-conformably by 

 the beds of the Wyoming Conglomerate, and underlaid, in the basin of Red 



