34 PALEONTOLOGY OF NEW YORK. 



Test not preserved Internal mould smooth. 



The specimen described consists of the chamber of habitation and fifteen 

 air-chambers, and measures 145 mm. in length and 64 mm. in greatest trans- 

 verse diameter. 

 Distribution. In the Upper Helderberg limestone, near Columbus, Ohio. 



O.OMrilOCERAS AIINUM. 

 PLATE CXXIt, FIG. 4. 



Gwnphoeeras mtoium, Hall. Fifth Ann. Kept. State Geologist. Expl. pi. (122) 7, fig. 4. 1883. 



Shell small, oviform; point of greatest transverse section on the anterior third 



of the tube. 



Chamber of habitation comparatively large and gibbous. Aperture small, 



trilobate. Air-chambers 2 mm. in depth. 



Test marked by lines of growth. 



Length of specimen 30 mm., greatest diameter 22 mm. 



The shell of the individual described is silicified and many of the features 

 are obscure. 



The species is distinguished by the small and ovoid shell. 

 Distribution. In the limestone of the Hamilton group, from the Falls of the 

 Ohio River, near Louisville, Ky. 



GOMPHOCERAS MANES. 

 PLATE CXXIII, FIG. 1 



Gomphoceras manes, Hall. Pal. N. V.. vol. v. pt. 2. p. 339. 1879. 

 GOMPHOCERAS NASUTUM. 



PLATE CXX, FIGS. 5-7. 



a ,h . a nasutum, Hall. Fifth Ann. Rept. State Geologist. Expl. pi. (120) 4, figs. 5-7. 1886. 



SHELL small, robust, nearly straight. Tube rapidly expanding to the middle of 

 the chamber of habitation thence gradually contracting to the aperture. 



