CRETACEOUS AND TERTIARY FORMATIONS 513 



Cannon Ball River, since they occur abundantly along that 

 stream. 



The following Fox Hills fossils were collected on the Cannon 

 Ball River about ten miles above its mouth: 1 



Tancredia americana M. and H. Avicula nebrascana E. and S. 



Callista deweyi M. and H. Protocardia subquadrata E. and S. 



Tellina scitula M. and H. Mactra warrenana M. and H. 



Ostrea pellucida M. and H. Mactra ? sp. 



Avicula linguiformis E. and S. Scaphites cheyennensis (Owen). 



The first three in the above list occurred in a bed of sandstone 

 forty feet below the top of the formation, while the others were 

 from a higher horizon, ten feet below the top of the Fox Hills. 



About three miles below this locality specimens of Mactra 

 warrenana M. and H., Dentalium gracile M. and H. ? and Cinulia 

 cincinna (M. and H.) ? were collected. 



On Long Lake Creek, a tributary of the Missouri River, from 

 the east the sandstone yielded the following: Avicula linguiformis 

 E. and S., Tellina scitula M. and H., and Chemnitzia cerithiformis 

 M. and H. ? 



The contact of the Fox Hills sandstone with the overlying 

 Lance formation is well shown in the bluffs on the north side of 

 the Cannon Ball River, about ten miles above its mouth. Here 

 the two formations are seen to be conformable, the top of the Fox 

 Hills being marked by a light gray, almost white sandstone, which 

 exhibits cross-bedding (Fig. 2). This bed is one foot to eighteen 

 inches thick. Sedimentation was apparently continuous from 

 Fox Hills time on into the period when the Lance beds were being 

 formed. 



East of the Missouri River, in Emmons County, the sandstone 

 is present on Beaver Creek, extending up the valley of that stream 

 almost to Linton, and having an elevation of nearly 150 feet above 

 the creek, near its mouth. 



About 160 miles west of the Missouri River, the Fox Hills 

 sandstone is exposed in a small area on Little Beaver Creek, in 

 the northwest corner of Bowman County, North Dakota. The 

 section here is as follows: 



1 Identified by Dr. T. W. Stanton. 



