228 CEPHALOPODS. 



Nautilus lawsi Swallow, 1860: Trans. St. Louis Acad. Sci., vol. I, 

 p. 658. Devonian limestone : Callaway county. Poorly defined. 



Orthoceras chemungense Swallow, 1860: Trans. St. Louis Acad. Sci., 

 vol. I, p. 660. Lithographic limestone : Marion county. Not recog- 

 nizable. 



Poterioceras missouriensis Miller, 1892 : Geol. Sur. Indiana, 18th Ann. Rep., 

 adv. sheets, p. 70, pi. xi, fig, 6. Probably a Phagmoceras, and in 

 that case the specific name is preoccupied. This original specimen 

 is an internal cast, and too imperfect to refer with certainty to its 

 proper genus. 



