290 



NORTH-CAROLINA GEOLOGICAL SURVEY. 



FIG. 215. 



trie striae ; umbo flattened ; apex sub-acute ; inner margin 

 entire. One of the most common fossils of the shell marl. 



O. GIBBESII : TUOMEY & HOLMES, FOSSILS OF SOUTH-CAROLINA J p. 74. 



(Fig. 215.) 



" Shell somewhat triangular, thick, con- 

 centrically furrowed ; buccal side rounded; 

 anal side somewhat beaked, angular, with 

 a longitudinal ridge ; umbones incurved; 

 lunule somewhat excavated." 



In addition to the foregoing, I may add the following as 

 common in the ]^orth-Carolina shell marl beds : Crassatella 

 alta, C. Marylandica, C. Protexta, C. Melina. 



FAMILY 



FIG. 21 SB. 



CYCLASIDAE. CORBICULA DENSATA. CYRENA DENSATA. 



CON . (Fig. 215A.) 



FIG. 215A. Shell orbicular striated concen- 



trically, polished, lateral teeth 

 elongated. 



This shell is very abundant at 

 the miocene marl bed of Mr. 

 Flower, on the Cape Fear. 



FA^SLY CORBULIDAE. CORBTTLA CU~ 



NEAT A. (Fig. 215B.) 



Shell small, thick, ovate, con- 

 centrically striate ; anterior margin rounded ; 

 posterior elongated, or somewhat rostrate. 

 Common in the shell marl. 



FAMILY LUCENIDAE. 



This family have orbicular shells, both free 

 and closed with hinge teeth, somewhat varia- 

 ble as one or two laterals, or one and one, 

 and the other obsolete ; pallial line simple, muscular im- 

 pressions two, elongated and rugose. The family is princi- 

 pally composed of tropical and temperate species, and live 



