HORIZON OF THE MARINE JURASSIC OF UTAH 639 



Canyon the basal Flaming Gorge contains heavy gypsum beds 

 occupying a position below this tan sandstone and above the two- 

 fold La Plata sandstones. In this locality the fossiliferous lime- 

 stones were not noted by the writer, but they are reported by 

 Gilbert^ west of Masuk Plateau. The localities in Water Pocket 

 Canyon are perhaps 30 or 40 miles southeast of where the Teasdale 

 collection was made. 



In the Water Pocket Canyon locality the Flaming Gorge beds 

 supposed to be McElmo are directly overlain by sandstones that 



■rk^^lf'sf:'- 



Fig. 4. — Lower La Plata (Vermilion Cli£f) sandstone, with characteristic arch, 

 overlain by thin-bedded red sandy shale (Todilto ?) in Mule Twist Canyon, Water 

 Pocket Flexure, near Henry Mountains, Utah. 



grade up into typical Mancos shale. From these sandstone beds 

 the writer collected the following fossils along Bitter Creek Divide. 

 Identifications were made by Dr. Stanton, who says:^ "The col- 

 lection from the sandstone near base of Mancos shale in Water 

 Pocket Canyon yielded a number of species that are known to be 

 characteristic of the sandstones in the lower part of the Mancos, 

 as follows: Ostrea prudentia White; Exogyra columhella Meek; 

 Exogyra sp., related to E. laeviuscula Roemer;* Exogyra sp., 

 related to E. ponderosa Roemer;* Gryphaea newherryi Stanton; 



' G. K. Gilbert, op. cit., Fig. 2. ^ Personal communication. 



*"White identified these two Texas species in collections from southeastern Utah 

 and I repeated his descriptions and figures under the same names in Bnll. 106 but I 

 now think them to be probably distinct." 



