270 STANTON 



Columna 



Viviparus trochiformis M. & H. ? 

 Campeloma muUilineata M. & H. 

 Goniobasis tenuicarinata M. & H. 



The fauna is closely related to that of Hell Creek and Converse 

 County. The lowest Fort Union plants recorded occur several hun- 

 dred feet higher, except a fig identical with one found in Converse 

 County and Hell Creek. 



Black Buttes, Wyoming. — This locality has been the subject of 

 much discussion ever since 1872, when the dinosaur, Agathanmas 

 sylvestris Cope, now referred to the Ceratopsia, was found there. 

 The following description by Stanton and Knowlton*' will show the 

 paleontologic characteristics of the dinosaur-bearing formation and 

 the relative positions of the various species: 



The most prominent feature of the section at Black Buttes is the 

 massive bed of sandstone, somewhat over 100 feet thick at the base of 

 the exposure, forming steep hills and cliffs northeast of the railroad 

 opposite the station and passing beneath the surface by its dip of 9 

 or 10 degrees near the coal mine. The upper portion of it is also 

 exposed on the south side of Bitter Creek valley, about a mile from the 

 station. All of the Laramie fossils, whether plants, invertebrates, 

 or vertebrates, that have hitherto been described or listed as coming 

 from Black Buttes were obtained from the overlying beds within about 

 100 feet of the top of this massive sandstone. The original specimen 

 of Agathaumas sylvestris was found about 20 feet above it, and the 

 plants that have been described came from the same horizon and from 

 several higher bands up to the bed overlying the principal coal, some 

 60 or 75 feet higher. The invertebrates from this locality have about 

 the same range. Most of the beds vary considerably in character and 

 thickness within short distances, but the fossiliferous and overlying 

 portions of the sections may be described in general terms as a series 

 of variable sandstones, clays, and coal beds exposed in low hills and 

 ridges with a dip of 9 or 10 degrees eastward at the base, but decreas- 

 ing in the upper portions to 5 or 6 degrees, which is about the same as 

 the dip of the overlying Wasatch beds. 



The character of the mollusks shows that the lower beds were mostly 

 deposited in brackish waters, but that there were alternations of fresh 

 waters in which the genus Unio thrived with an abundance of individ- 

 uals and great variety of species, [and several fresh-water gasteropods 

 were common. Between the top of the massive sandstone and the 



*^ Bull. Geol. Soc. America, Vol. VIII, 1897, pp. 143-145. 



