30 (J incinnati Society of Natural History. 



Prof. C. A. White described from the Flaming Gorge Group, Green 

 river, near the northern boundary line of Utah, Unio stewardi, and 

 from the mouth of Thistle Creek, Spanish Fork Canon, Utah, Neritina 

 pQwelU. 



R. P. Whitfield * described from the Jurassic in the Bridger Moun- 

 tains, Montana, Gryphaea plauoconoexa, Gervillia sparsalirata and 

 Myalina perplana. 



Dr. F. V. Hayden,f speaking of the Triassic Group of Colorado and 

 the West, as late as 1876, says: 



The Red Beds or Triassic Group is very persistent, and if absent at 

 all, only at very shorr intervals. No organic remains have yet been 

 found in this group, by the members of the survey under my charge, 

 yet, for various reasons, we have assumed the red sandstones to be of 

 Triassic Age. It is barely possible that a portion or all of the Group 

 is of Jurassic Age. Yet Prof Cope is of the opinion that he has dis- 

 covered evidence in New Mexico of its Triassic Age. The history of 

 this Group is still obscure, and remains as one of the problems to be 

 solved by more extended and more thorough explorations. Geograph- 

 ically it is one of the most widely distributed formations in the west. 

 From the northern boundarj^ to the southern line and east of the Wa- 

 satch range, in Utah, this red formation makes its appearance wherever 

 a mountain range is elevated so as to expose the various sedimentary 

 groups. The evidence indicates that it extends without any import- 

 ant interruption over the broad area as defined above. These red 

 sandstones have alwaj^s attracted much attention, on account of their 

 peculiar color, but nowhere have I ever observed them performing such 

 a conspicuous part in giving form to the scenery of the countrj', as 

 along the eastern base of the Rocky Mountains in Colorado. This 

 feature is more marked from a point about fifty miles north of Denver 

 to Colorado Springs, than in any other portion of the continent. Along 

 this belt the sandstones are more compact, with every variety of red, 

 from a pale, dull tint to a deep purple color. There is also ever}^ 

 variet}^ of texture, from a rather coarse conglomerate to a fine sand- 

 stone. It varies much in thickness, ranging from 400 to 2,000 feet. 

 These sandstones in Pleasant Park, the '■ Garden of the Gods," and 

 other places have been weathered into the most fantastic shapes, and 

 stand up in immense walls or columns from 50 to 250 feet in height. 



Dr. A. C. Peale found Permian fossils in the beds below the red 

 sandstones referred to the Triassic, and as Dr. Hayden and others had 



* Carroll to Yellow Stone, Nat. Park. 

 t U. S. Geo. Sur. Terr. 



