66o 



NORTH AMERICAN INDEX FOSSILS. 



■ 



elevated ; angulation nearly median as viewed from above. Diame- 

 ter one third inch or less. 



Fig. 908. Euomphalus latus. (After Keyes. ) 



St. Louis of Illinois ; Maxville of Ohio ; Batesville of Arkansas. 

 181. E. planidorsatus M. and W. (Fig. 910.) Mississippi. 



Fig. 909. Euomphalus similis. (After Whitfield, N. Y. Acad. Sci. Trans.) 



Similar to the preceding but about an inch in diameter ; angu- 

 lation somewhat nearer to periphery. 

 Chester of Illinois, Missouri, etc. 



Fig. 910. Euomphalus planidorsatus. (After Meek and Worthen, Pal. III., II.) 



182. E. pernodosus M. and W. (Fig. 911.) Carbonic. 



Large, up to two inches in diameter. Spire flat, shoulder 



