Mesozoic and ConnSzoic Geology and Paloiontology. 107 



bluffs rise to a height of 200 feet, the yellow strata constituting the 

 upper half. Half way between this point and the fort, Haploscapha 

 qrandis, and H. eccentrica occur. Some of them are twenty-seven inches 

 in diameter. Fragments of Anogmius occur in the yellow bed and 

 Tnoceramus problematicits in the blue. 



Along the Smoky Hill river, 30 miles east of Fort Wallace, the strata 

 have a gentle dip to the northwest. The 3'ellow and the blue strata are 

 about equally fossiliferous and pass into each other by gradations and ' 

 by slight laminar alternations at their line of junction. Cimolichthys 

 semianceps, Liodon glandiferus^ and L. dyspelor occur in both classes 

 of strata. The yellow strata are remarkably uniform in mineral con- 

 tents, but the blue contain numerous concretions and great abundance 

 of thin laj^ers of gypsum and crystals of the same. Near Sheridan, 

 concretions and septaria are abundant. In some places the latter are 

 of great size, and being imbedded in the strata have suffered denuda- 

 tion of their contents, and the septa standing out form a huge honey- 

 comb. This region, and the neighborhood of Eagle Tail, Colorado, 

 are noted for the beauty of their gypsum crystals. These are hex- 

 agonal-radiate, each division being a pinnate or feather-shaped lamina 

 of twin rows of crystals. The clearness of the mineral and the regular 

 leaf and feather forms of the crystals give them much beaut3\ The 

 yellow bed disappears to the southwest, west, and northwest of Fort 

 Wallace, beneath a sandy conglomerate of Tertiary age. 



He described, from the Fort Benton Group, at Bunker Hill station, 

 Kansas, Apsopelix sauriformis. 



He described, from the Niobrara Group, near Eagle Tail in Colorado, 

 Liodon crassartus, now Platecarpus crassartus; from Kansas,* 

 Ornithochirus harpyia^ 0. umhrosus; from near Butte creek, Cynocer- 

 cus incisus; from Sheridan, Plesiosaurus gulo.\ 



He determined]; the Upper Cretaceous age of the Li^hitic strata of the 

 Bitter Creek Basin of Wyoming, and described, from near Black Buttes 

 station, on the U. P. R. R., 52 miles east of Green river, and near the 

 Hallville coal mines, Ayathaumas sylvestris. This dinosaurian was 

 discovered between the thinner or lower strata of the Bitter creek 

 series of coal, which at this point occupy a position of elevation and 

 crop out high on the bluffs. Two strata appear above the sandstone 

 in which the bones occur, and one below it. 



■-^- Proc. Am. Phil. Soc. 

 t Proc Acad. Nat. Sci. 

 X Pal. Bull. No. i and No. 10, and Proc. Am. Phil. Soc 



