PLATE LXXXI 



PAGE 



Figs. 1-9. PLATYCERAS GEBHAKDI VAR. VEXTRICOSUM Conrad 471 



1, 2. Upper and ventral views. 



3, 4. Ventral and upper views of a small individual. 



5, 6. Upper and ventral views of a specimen of medium size. 



7, 8. Upper and ventral views of a large specimen with contiguous 



volutions. 

 9. Upper view showing a broad sinuosity in the margin. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



73 



