199 



Genus Scalpellum, Leach. 



S. IN^QUIPLICATUM, (n. sp.) Shell depressed conical, length 

 about one third greater than the height ; apex situated nearer the 

 anterior margin than the centre ; surface marked with prominent 

 unequal folds or costa3, which commence at the beak and radiate to 

 the lateral and front margins ; posterior side smooth, or marked with 

 one or two obscure, longitudinal elevations. The number of ribs on 

 the only specimen I have seen amounts to eleven, those of the left 

 side being smaller and more numerous than those of the right. 



The specimen is so embedded in the matrix that the interior char- 

 acters cannot be made out. It is therefore only placed provisionally 

 , in the above genus. 



Length, 1:^ inch ; height, 7^ lines. 



Ripley Group, near Chatfield Point, Navarro County. 



Collected by Dr. G. G. Shumard. 



CONCHLFERA. 

 Genus Pholadomya, Sowerby. 



P. LixCECUMi, (n. sp.) Shell below medium size, very thin, sub- 

 pyriform, length double the width, width and thickness about equal, 

 gibbous and broadly rounded before, narrowing towards the posterior 

 margin, which is rounded and gaping ; buccal margin sinuate ; cardi- 

 nal margin straight ; beaks but little elevated, rounded, situated near 

 the anterior margin ; surface ornamented with about thirty radiating 

 raised lines, crossed by narrow concentric, sinuate folds and five strias 

 of growth. The radiating lines are closer together on the middle 

 region of the shell than at the extremities, and are frequently inter- 

 rupted by the furrows between the folds ; the whole surface, except 

 a small space at each extremity, presenting a beautifully cancellated 

 appearance. 



Length, 1.12 inch; width, 0.58. 



We have found but a single specimen of this species in the Ripley 

 Group at Corsicana, Navarro County. 



The species is dedicated to Dr. Gideon Lincecum of Long Point, 

 Washington County, to whose liberality the State Cabinet is indebted 

 for a number of interesting fossils. 



Genus Paxop^a, ISlenard. 



P. SUBPLICATA, (n. sp.) Shell large, subovate, approaching sub- 

 quadrate, length in young individuals nearly double the width, be- 

 coming proportionally shorter with age ; anterior extremity strongly 

 rounded, gaping ; anal end broadly truncate, rounded above and 

 below, widely gaping ; cardinal and pallial margins subparallel ; beaks 

 situated a little nearer the anterior than the posterior end, depressed, 



