570 NORTH AMERICAN INDEX FOSSILS. 



obliquely forward just in front of the beak, ending about half way 

 between the dorsal and ventral margins. 



Benton : Colorado ; probably similar age in Utah. 



CLXXIL Leptosolen Conrad. 



Thin. Beaks anterior. Epidermis unpolished. A strong 

 internal rib directed vertically extends from beak to basal margin. 

 Pallial sinus very shallow. Hinge with a single cardinal tooth in 

 each valve. Comanchic-Cretacic. 



582. L. conradi Meek. Comanchic. 

 Differs from L. biplicatus in its smaller size (average length 1 



inch ; height .35 inch) and in the absence of the two plications. 

 Upper Comanchic of Kansas and Colorado. 



583. L. biplicatus Conrad. Cretacic. 

 Anterior extremity compressed, marked with two obscure pli- 

 cations extending obliquely forward and downward from the beak. 

 Surface covered with inconspicuous growth lines. Average length 

 1.5 inches ; height .5 inch. 



Ripleyan of New Jersey (Cliffwood-Red Bank), Gulf region. 



CLXXIII. Solyma Conrad. 



Elongate-ovate, thin, equilateral, ventricose. 

 Right valve with two cardinal teeth. Cre- 

 tacic. 

 584. S. lineolata Conrad. (Figs. 782, 783.) 



Fig. 782. Solyma lin- ' Cretacic 



eolata. (After Whitfield, . . 



Pal. N. J., I.) Posterior margin truncate. Both anterior 



and posterior umbonal slopes marked by an 

 obscure ridge. Surface of internal molds marked with fine and 

 irregular concentric lines. Type of genus. 



Fig. 783. Solyma lineolata, interior of Fig. 782 and enlargement of hinge. 

 (After Whitfield, Pal. N. J., I.) 



Ripleyan of New Jersey (Cliffwood-Red Bank), Georgia. 



