NORTH-CABOLINA GEOLOGICAL SURVEY. 



291 



upon sandy or muddy bottoms, and exist from the sea shore 

 or shallow water to the greatest habitable depths. 



LUCINA BEUGIEEE. 



The shell is orbicular, white, with depressed umbones, and 

 the margins are either smooth or only finely crenulated; 

 hinge teeth 2 2, laterals 11, muscular impressions rugose ; 

 anterior, elongated and within the pallial line ; umbanal area 

 with an oblique furrow. 



LUCINA PENNSYLVANIA. LINN. (Fig. 216.) 



Shell orbicular, thick, solid, and concentrically ribbed, or 



posteriorly it has a strong 

 fold or groove. The fold ex- 

 tends across the shell, and 

 produces a notch in the pal- 

 lial margin. Common in the 

 miocene upon K"euse and 

 Cape Fear rivers. 



FIG. 216. 



LUCINA CONTRACTA. 



Shell orbicular, somewhat 

 inflated ; ribs concentric, un- 

 equal, marked in the intevals 

 with striae ; posteriorly the 

 margin is channeled. 



It is larger than the preceding, and has no fold, and its 

 ribs are unequal. 



FIQ. 217. 



L. CEENULATA. (Fig. 217.) 



Shell small, thin, orbicular, somewhat inflated, 

 jfif\^ concentrically lamellated, lunule excavated- 



1 iggjjy In addition to the foregoing, the following 

 species have been observed in the miocene : 

 Lucina anadonta, L. radians, L. divaricata, L. multihineata, 

 and L. squamosa. 



