PLATE LXXXIII 



PAGE 



Figs. 1-3. PLATYCERAS SUBFALCUM Ohern n. sp 472 



1. Upper view of a large specimen. 



2, 3. Views of type. 



Oriskany formation, Ridgely member, Hancock. 



Fig. 4. PLATYCERAS PATULUM Hall 473 



Ventral view. Oriskany formation, Ridgely member, Cumberland. 

 (After Hall.) 



Figs. 5, 6. PLATYCERAS REFLEXUM Hall 473 



5. Ventral view of a small specimen. 



6. Upper view of a larger specimen. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



74 



