303 Crown Point Section 37 



RAFIN/SOU/XA Hall and Clarke 



Rafinisquina champlainensis sp. nov., PI. iS, fi^s. 5, 6 



Shell large, ventricose, almost heinisperical in some speci- 

 mens. Length is to width as 6:7. Hinge line longer than the 

 greatest width below; cardinal extremities often produced into 

 short, broad, rounded ears; beaks small; ventral valve ver\" con- 

 vex, greatest convexity being about the middle of the valve; dor- 

 sal valve concave, but does not follow exaclly the curvature of 

 the ventral, the umbo being flattened. 



Surface marked by numerous fine radiating striae, about every 

 third or fourth one being stronger than the ones between. The 

 striae increase toward the front b}' implantation. In the partiall)'' 

 exfoliated state in which the specimens are usually found, the 

 striae appear nearly equal and the shell rather fibrous. 



Locality. — In the middle portion of the Chazy at Crown 

 Point, A'alcour Island, Maclurea Point, and elsewhere along 

 Lake Champlain. 



STROPHOMENA Rafinesque (de Blainville) 



Strophomena incurvata Shepard, PI. 19, fig. n 



This well-marked fossil is rather common all through the 

 Black River limestone in this section, but does not cross the line 

 into the Trenton. It is reported as common in the Trenton of 

 Minnesota, but in eastern and northern New York it is common 

 only in the Black River and may be considered a characteristic 

 fossil. 



Locality. — Black River limestone. Crown Point, N. Y. 



TRIPLECL4 Hall 



Triplecia gracilis sp. nov., PI- i*^> fiK- 1 



Shell small, nearly circular in outline, both valves moderatel\- 

 convex; greatest convexity about the middle of the valves; beaks 

 small, that of the donsal valve hardly extending beyond the hinge 

 line; cardinal line short. The dorsal valve has a small rounded 



