164 



NEW YORK STATE MUSEUM 

 PLATE 11 



Dawsonoceras annulatum americanum Foord 



(See plate 10, fig. 19-21) 



Page 80 

 IC. 



i A large individual from the Lower Shelby bed. 

 Orthoceras crebescens Hall 



(See plate 10, fig. 24, 27, 28) 

 Page 80 



2 Fragment of internal cast, showing septal sutures and obscure 



longitudinal ridges 



3 Internal cast of a fragment of an old individual, showing 



curved septal sutures, relatively deep camerae and septa 

 and low longitudinal ribs. 



4 An internal cast of the living chamber and camerae of an old 



individual, showing the sinuate growth lines on living 

 chamber and shallow gerontic chambers 



