TRIASSIC PORTION OF SHINARUMP GROUP 121 



disclose the fossiliferous horizon in the Uinta Mountains. From the 

 relations found on Grand River, it seems probable that the equivalent 

 of the "saurian conglomerate" occurs near the Vermilion Cliff 

 sandstone if present at all in the Uinta section. 



The only statement I have found in regard to the Trias of the 

 Uintas suggesting the presence of the fossiliferous horizon of the 

 Dolores formation, or, as it might be otherwise interpreted, of the 

 Shinarump conglomerate, is a passage from King's description of 

 the section on the northern slopes of the mountains near Vermilion 

 Creek. He remarks that the basal portion of the Trias consists "of 

 red conglomerate-bearing sandstones which carry a seam of drab 

 limestone. Above these is a body of red sandstone of several hundred 

 feet" (14, p. 259). This heavy sandstone seems to correspond to 

 the Vermilion Cliff sandstone, for above it comes a lighter- colored 

 cross-bedded sandstone answering to the White Cliff or La Plata 

 sandstone. Emmons describes the same section in similar terms 

 (10, p. 275). Presumably the "conglomerate-bearing sandstone" 

 is quite near the Vermilion Cliff and this at once suggests comparison 

 with the Grand River section. 



The foregoing discussion has not taken into account the lower 

 Triassic beds of southeastern Idaho, often termed the "Meekoceras 

 beds" from characteristic marine fossils they contain. These beds 

 are not known in any of the areas referred to in this paper. If ever 

 present in Colorado or the Plateau Province the marine lower Tri- 

 assic beds must have been removed by the pre-Dolo'res erosion. 

 The interesting problem as to the relations of the Meekoceras beds 

 to the so-called Permian or Permo- Carboniferous formations of Utah 

 is clearly beyond the scope of this paper. 



It is hoped that the foregoing discussion will have made clear 

 to the reader that there are strong reasons for correlating the Triassic 

 portion of Powell's Shinarump Group with the lower part of the 

 Dolores formation of Colorado. The fossiliferous "saurian con- 

 glomerate " of the Dolores has been traced into the heart of the Plateau 

 country and a notable unconformity found below it there as well as 

 in the San Juan Mountains of Colorado. The reptilian fauna of 

 the "saurian conglomerate" has been found on the Little Colorado, 



