234 Annals of the Carnegie Museum. 



third or fourth one of which is stronger than the ones between. The 

 striae increase by implantation. In the partially exfoliated state in 

 which the specimens are usually found, the striae appear nearly equal 

 and the shell structure fibrous. 



Locality. — The range of this shell seems to be the same as that of 

 Maclurites magnus. It is very abundant at Maclurea Point, Crown 

 Point, Valcour Island, Bluff Point, and Chazy, New York, and Isle 

 la Motte and South Hero, Vermont. 



1 6. Rafinesquina distans Raymond. 



(Plate XXXV. figure i.) 

 Rafinesquina distans Raymond, 1906. Annals Carnegie Museum, Vol. Ill, p. 575. 

 This is a small, fairly common shell, usually found in the upper 

 part of the Chazy, associated with Camaroteechia plena. It is also 

 found in the dolomitic limestone of the reefs. 



Description. 



Shell small, nearly flat, about three-fourths as long as wide. The 

 greatest width is at the hinge. The sides and front are regularly 

 rounded. The surface is marked by eight to twelve prominent striae, 

 between which are groups of from ten to fifteen very fine striae. There is 

 no other species in the Chazy on which the principal striae are so widely 

 separated, and it can be easily distinguished by this character. 



Locality. — -Rare in the middle of the Chazy at Crown Point, and 

 common in the Upper Chazy at Valcour Island. 



Genus Strophomena Blainville. 



17. Strophomena prisca Raymond. 



(Plate XXXV, figures 2, 3.) 

 Strophomena prisca Raymond, 1905. American Journal of Science, Vol. XX, 

 series 4, p. 369. 



The genus Strophomena, which has not previously been known in 

 American faunas older than that of the Black River, is represented 

 in the Chazy by a rare form, of which only a few specimens have been 

 found. 



Description. 



Shell of medium size, resupinate, nearly as long as wide. Pedicle 

 valve convex at the umbo, flat in front to about the middle of the 



