75o 



NORTH AMERICAN INDEX FOSSILS. 



non-angulate, the preceding two or three are angulate ; while the 

 earlier ones are more or less flat and ribbed. Lip drawn out at 

 each end to form a narrow, deep canal. 



Caloosahatchie beds of Florida. 

 489. C. (Potamides) scalatum Heilprin. (Fig. 1088.) Pliocenic. 



Fig. 1086. a, Cerithium Fig. 1087. b, Cerithium Fig. 1088. c, Potamides 

 hillsboroense, X J -3- (After caloosa'e'nse, X %• (After (Pyrazisinus) scalatus,y^\. 

 Dall.) Dall.) (After Dall.) 



Whorls round, slightly concave below the suture, ribs simple, 

 not reaching to upper suture ; faint spirals between ribs ; outer lip 

 broadly notched. 



Caloosahatchie beds of Florida, etc. 



Family Aporrhaid^e Philippi. 



CXXXV. Anchura Conrad. 



Turreted shells with the base drawn out into a long canal, 



and the outer lip prolonged into a single wing-like expansion 



which may divide terminally, but is often broken away in the 



specimens. Comanchic-Cretacic. 



490. A. kiowana Cragin. Comanchic. 

 Differs from the next in its somewhat shorter spire, more pro- 

 nounced costae, roundness of body whorl, and restriction of carina 

 nearly to falcate process of lip, which is only slightly upturned. 



Kiowa shales (Washita) of Kansas. 



49 1. A. exilis Gabb. (Fig. 1089.) Cretacic. 

 Small, whorls rounded except for strong median carina of body 



whorl, above which shoulder is concave ; ribs low and faint. 



