Mesozoic and Cmnozoic Geology and Paloiontology. 249 



where the beds have an estimated thickness of 5,000 feet, Diceratheri- 

 um armatum, D. nanum, Thinohyus lenfus, and T. socialis. 



T. A. Conrad* described, from the Eocene at Wilmington, North 

 Carolina, Terebratida demissirostra; and from Beaufort, Pecten ani- 

 sopleura and P. caj'olinensis. 



From the Miocene near Wilmington, and other places in North Car- 

 olina, Liropecten carolinensis, Ostrea perlirata, Placunomia fragosa, 

 Raeta alta^ B. erecta, Ahra hella, A. holmesi, N'oetia proiexta, N'.fllosa, 

 Mercenaria carolinensis. Leptothyris parilis, Trachycardium bellum 

 Mysia carolinensis, Saxicava protecta, Turritella perexilis, T. caroUn- 

 ensis, Fissurella caroUneiisis^ Littorina carolinensis, Busycon herri^ B. 

 amoenum, and B. concinnum ; from Suffolk, Va., Zizyphus virginiciis. 



W. H. Dalit described, from the Miocene at Cerros Island, California, 

 Waldheimia kennedyi; from the Pliocene at San Diego, Chrysodomus 

 diegoensis. AndR. C. StearnsJ described, from the same strata, Opalia 

 anomala, and 0. varicostata. 



In 187(5, Prof. J. W. Powellg subdivided the Tertiary rocks of the 

 plateau province of the west in ascending order, into the "Bitter Creek 

 Group," which is synonymous with the Wasatch Group, and has a 

 thickness of 5,000 feet. It is succeeded hy the Lower Green River 

 Group, consisting of shales, often bituminous; sandstones; carbonace- 

 ous shales and lignitic coal near the base. Thickness, 800 feet. 



This group is well exposed along Green river, from Green River 

 station southward for 10 miles; in many of the escarpments of the Quien 

 Hornet mountain, and a few miles northeast from the head of Ver- 

 milion canon ; on Snake river, six miles above the northern foot of 

 Junction mountain; and on the elevated ledges known as Pine Bluffs, 

 near the sources of the eastern tributaries of Vermilion creek. The 

 beds are all fresh water. 



The Upper Green River Group consists of sandstones, sometimes 

 argillaceous limestones, carbonaceous shales and lignitic coal, near the 

 middle and in the lower part massive or irregularly bedded sandstone, 

 ferruginous. Unconformable by erosion with lower Group. Thickness, 

 500 feet. 



The plant beds of this group are well exposed to the north of Green 

 River station, and between that point and Alkali stage station, in 

 many gulches and canons; in the cuts of the Union Pacific Railroad 



* Geo. of N. Carolina. 

 i Proc. Cal. Acad. Sci., vol. v. 

 t Proc. Acad. Nat. Sci. Phil. 

 g Geo. of Uinta Mountains. 



