HUDSON-KIVER GROUP. 



307 



240. 1. BELLEROPHON BILOBATUS. 



Pl. LXXXIII. Figs. 9 a, b, c. 

 Reference pag. 184, pi. 40, figs. 3 a, b, c, d, of this volume. 



This fossil is far less abundant in the Hudson-river group than in the Trenton limestone, 

 but still it is seen in nearly every locality where the rocks are well exposed. The shell is 

 rarely preserved, and the casts show the small umbilicus very distinctly. This fossil often 

 attains a greater size in this group than in the Trenton limestone. The specimens found 

 are usually compressed, and it rarely presents the rotundity so common in the limestone. 



Fig. 9 a. A large imperfect specimen. 



Fig. 9 b, e. Lateral and profile view of a smaller specimen, showing the volutions compressed, as in 

 some of the varieties from the Trenton limestone. 



Position and locality. This species is rarely seen in the lower shaly part of the group, 

 but in the central semicalcareous strata it is of frequent occurrence. Specimens have been 

 obtained from Turin, Pulaski, Loraine, and several other localities. 



{Statt Collection.) 



368. 4. BELLEROPHON CANCELLATUS (n. SJ9.). 

 Pi.. LXXXIII. Figs. 10 a, b, c. 



Involute, subglobose ; aperture expanded, bilobate ; dorsal line subcarinated ? ; surface 

 cancellated by fine concentric and longitudinal striae ; concentric striae arching on the side, 

 and meeting at a sharp angle upon the dorsal line ; aperture with a sinus in the dorsal 

 margin. 



The concentric striae are usually the more conspicuous, the others being scarcely visible, 

 except under a magnifier. The only entire specimen seen is crushed, so that the original 

 form cannot be clearly defined ; but the marking of the surface js sufficient to distinguish 

 it from any other species in the lower strata. 



Fig. 10 a. Lateral view of an entire individual. 



Fig. 10 b. A portion of the surface enlarged, showing the cancellated striae. 



Fig. 1 c. A fragment of a shell, apparently of the same species. 



Position and locality. The perfect specimen, with one or two fragments of the same 

 species, was found at Loraine ; and the small fragment figured, in the partially altered 

 shales near Waterford, these being the only localities where it is known to occur. 



{State Collection.) 



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