TRENTON tIMESTONE. 183 



Genus C A R IN A R P S IS. 



[Carinaria, and o^n; from its resemblance to Carinaria.] 



Character. Symmetrical, subconical, patelliform, subangulated or carinated on the dorsal 

 line ; apex incurved or convolute ; aperture oval, narrowed posteriorly. 



There are two or three species of shells having the characters here given. They are 

 usually associated in the rock with the Belkrophon bilobatus, and are rarely seen in any 

 other situation. 



238. 1. CARINAROPSIS CARINATA (m. *p.). 



Pl. XL. Figs. 1 <i!, i, c. 



Depressed conical ; apex incurved ; aperture broadly expanded, with a narrow sinus in 

 the posterior dorsal margin, from which a strong dorsal carina extends to the apex ; surface 

 concentrically striated. 



This species is remarkable for the broadly expanded aperture and sudden contraction 

 towards the apex, which is acutely pointed and incurved. 



Figs. I a, b. Lateral and dorsal views. 



Fig. 1 c. Lateral view of another specimen, showing a more elevated carina. 



Position and locality. In the dark compact limestone at Middleville and Trenton Falls, 

 associated with the Belkrophon bilobatus. 



239. 2. CARINAROPSIS PATELLIFORMIS (n. *p.). 



Pl. XL. Figs. 2 a, b. 



Obliquely subconical, patelliform, the apex incurved and extended in a line with or 

 beyond the margin, obtusely carinated upon the dorsal line ; aperture broadly oval, slightly 

 narrowed posteriorly ; surface marked by fine concentric sublamelliform striae. 



This species resembles in form the recent Capulus ; but the structure of the shell is quite 

 different, being, in this respect, closely allied to the Bellerophon. There are one or two 

 other species in the Hudson-river group, and a single more elevated one in the Trenton 

 limestone, which has not been satisfactorily determined. 



Fig. 2 a. Dorsal view. Fig. 2 b. Lateral view of the same specimen. 



This one and the preceding species are arranged in this connection, both from similarity 

 in the structure of the shell to Bellerophon, and from an analogy in the form of C carinata. 



Position and locality. In the compact finegrained limestone, with the preceding species, 

 at Middleville. 



