50 SEDIMENTARY GROUPS OF THE PLATEAU PROVINCE. 



summit of the next group. No examination of the section has been made 

 along this line nor have the beds been studied in detail, but the upper and 

 lower limits of the gfoup are tolerably well defined. On the Green River, 

 about two miles and a half above Flaming Gorge, the junction between the 

 black shales of the lower group and the yellow shales of the upper can be 

 well seen, and the junction between this group and the Point of Rocks 

 Group is also well seen. Here the beds stand on edge and were measured, 

 and a thickness of nearly 2,000 feet obtained. This group can be well 

 studied in narrow zones along the northern flanks of the Uinta Mountains. 

 Fine exposures occur in the Pink Cliffs and at Gunnison's Butte on the 

 Green River south of Gray Canon, and north of the point where that river 

 was crossed by Captain Gunnison on his trip to Utah in 1853. 



SULPHUR CREEK GROUP. 



This group of black shales can be well seen in the hills near Hilliard 

 Station on the Union Pacific Railroad. Here Sulphur Creek cuts through 

 them for several miles. In Professor Meek's "Section on Sulphur Creek 

 near Bear River," his "No. 1" is the summit of the group. The locality 

 does not present a good type from the fact of the great displacements to 

 which the beds have been subjected. Their relation to underlying beds can- 

 not be determined with certainty; but on the north and south sides of the 

 Uinta Mountains many fine exposures are found. I have already mentioned 

 the point where the junction of this group ,with the overlying can be seen, 

 north of Flaming Gorge; the beds dip to the north at an angle of nearly 

 90 degrees, and on the south side of Henry's Fork the junction of the black 

 shales with the next group is plainly seen. Here the beds were measured 

 and found to be 2,050 feet in thickness. . 



Farther eastward between the head of Dry Lake Valley and Vermilion 

 Creek the beds dip to the north at an angle of about 25 degrees and are 

 truncated with the great Uinta flexure. Still farther south in the Escalante 

 Valley, Paria Valley, Kanab Valley and many other localities, the entire 



group is well exposed. 



HENRY'S FORK GROUP. 



This group can be well studied at the typical locality which is on the 



