636 W. D. SMITH 



All of these, and many more, are figured in the reports of the 

 Hayden Survey of the Territories, and by Stanton, 1 and referred to 

 the Fort Pierre horizon of the Upper Cretaceous. 



Stanton records a similar fauna from the Cretaceous rocks of 

 Nebraska, where the following species are contained in dark gray 

 and bluish plastic clays: 



Nautilus dekayi Dentalium graciale 



Placenticeras placenta Crass at ella evansi 



Baculites ovatus Cuculala nebrascensis 



Scaphites nodosus Inoceramus sagensis 



Inoceramus nebrascensis Inoceramus vanuxemi 



Bones of Mosasaurus missouriensis 



The beds also occur on Sage Creek, Cheyenne River, and on 

 White River above the Mauvaises Terres in South Dakota. Mr. 

 Stanton also states that these same beds are exposed in central Colo- 

 rado and contain: 



Nautilus dekayi Sphenodisctis lenticulare 



Baculites ovatus Scaphites nodosus 



Baculites compressus Ptychoceras mortoni 



Inoceramus cripsii Heteroceras (several specimens) 



Inoceramus proximus Anisomyon 



Placenticeras placenta Lucina occidentalis 



Avicula linguiformis Avicula nebrascensis, etc. 



Clearly, then, the suite from Montana belongs to the Fort Pierre 

 horizon of the Upper Cretaceous, and is, as far as we know, confined 

 to that horizon only. Scaphites nodosus certainly is characteristic of 

 that horizon. 



The other group of Scaphites is from the Pacific coast province 

 and from the horizon known as the Lower Chico, Upper Cretaceous. 

 The specimens I have used were collected and described by Mr. 

 F. M. Anderson, 2 paleontologist for the California Academy of 

 Sciences, from the '49 mine near Phcenix, Ore. 



These occur in soft, yellowish sandstone, with the following 

 ■characteristic fossils: 



1 T. W. Stanton, The Colorado Formation and its Invertebrate Fauna, 1893, 

 Bulletin No. 106, U. S. Geological Survey. 



2 F. M. Anderson, "Cretaceous Deposits of the Pacific Coast," Proceedings of 

 ihe California Academy of Sciences, 3d series (1902), Vol. II, No. 1. 



