PLATE LXXX 



PAGE 



Fig. 1. PLEUROTOMARIA LABROSA Hall 465 



Dorsal view of partially exfoliated specimen, preserving spiral band. 

 Also an enlargement of the surface markings. Becraft forma- 

 tion, New York. 



Figs. 2-9. PLATYCERAS GEBHARDI Conrad 470 



2. Lower and upper views of a large specimen. 



3, 4. Upper and ventral views of small specimen. 



5. Upper view of very large specimen from Warren Point, Penna. 



6, 7. Ventral and upper views of specimen with free and expanded 



peristome. 



8, 9. Upper and lower views of specimen with free but not expanded 

 peristome. 



Oriskany formation, Ridgely member, Cumberland. (All but 

 fig. 5 after Hall.) 



71 



