278 



NORTH-CAROLINA GEOLOGICAL SURVEY. 



EXOGYRA COSTATA.- 



FIG. A. 



[Fig- A.) 



Shell sub-oval, very thick, 

 lower valve convex, and cov- 

 ered with strong corrugated 

 ribs; apex lateral, with about 

 two volutions; upper valve 

 flat, thick, supplied with nu- 

 merous elevated concentric 

 squamose plates. It belongs 

 to, and is, one of the charac- 

 teristic fossils of the green 

 sand at Black Rock, on the 

 Cape Fear, and at Rocky 

 Point, twenty miles north of 

 Wilmington. It is found in 

 the miocene at several places on the Cape Fear, but its pres- 

 ence is due to accident. 



FIG. B. 



CUCULLAEA VULGARIS. (Fig. B.) 



This fossil occurs in the form of an in- 

 side cast of the shell ; it is inflated, sub- 

 triangular, flattened before, beaks prom- 

 inent and in-curved; shell thick, and 

 marked with numerous delicate longitu- 

 dinal striae. 



It is associated with the Exogyra and 

 Belemnitella at Black Rock in the green 

 sand. 



The C. vulgaris is placed here fromite 

 association with the E. costata. 



FAMILY PECTENIDAE. PECTEN, SCALLOP. 



Shell sub-orbicular, regular, resting on the right valve, 

 usually ornamented by fretted or scaly ribs radiating from 

 the hinge ; right valve most convex, with a notch below the 

 front ear ; hinge margin straight, united by a narrow liga- 

 ment ; cartilege internal in a central pit. 



