GUELPH FAUNA IN THE STATE OF NEW YORK 169 



FIG. 



10 Internal cast of an older individual with deeper chambers and 



obscure longitudinal ribs 



All figures are natural size. The originals of fig. 1-5, 7-9 

 are from Rochester (Arey collection) ; those of fig. 6 and 10 from 

 the Lower Shelby bed (N. Y. State Museum). 



Cyrtoceras cf. brevicorne Hall 



Page 89 



1 1 Fragment showing the living chamber and sinuous growth 



lines. Natural size. Rochester (Arey collection) 



12 Mold and internal cast of a fragmentary specimen, showing 



the amount of curvature and the unequal depth of the 

 camerae. Lower Shelby bed (N. Y. State Museum) 



Poterioceras sp. 



Page 97 



13-16 Four views of the internal cast of the living chamber of the 

 only specimen observed, showing the contraction of the 

 chamber and the submarginal position of the nummuloidal 

 siphuncle. Lower Shelby bed (N. Y. State Museum) 



