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NEW YORK STATE MUSEUM 

 PLATE 11 





Dawsonoceras annulatum americanum Foord 



(See plate 10, fig. 19-21) 



Page 80 



A large individual from the Lower Shelby bed. 

 Orthoceras crebescens Hall 



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

 Page 80 



Fragment of internal cast, showing septal sutures and obscure 



longitudinal ridges 

 Internal cast of a fragment of an old individual, showing 



curved septal sutures, relatively deep camerae and septa 



and low longitudinal ribs. 

 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 



