PLATE LXI 



PAGE 

 FigS. 1, 2. SCHUCHERTELLA DEFORMIS (Hall) 331 



1. View of the dorsal valve and area of the ventral valve. 



2. Ventral valve of the same specimen, showing the contracted and 



distorted beak. 



Helderberg formation, Keyser member, Cumberland. (After 

 Hall.) 



Figs. 3, 4. SCHUCHERTELLA sixuATA (Hall and Clarke) 331 



Dorsal and cardinal views. Helderberg formation, Keyser member, 

 Cumberland. (After Hall and Clarke.) 



Figs. 5-9. SCHVCHERTEIXA MARYLAxniCA Maynard n. sp 332 



5, 6, 7. Ventral, dorsal, and cardinal views of type specimen. 

 8, 9. Partially exfoliated dorsal valves, Keyser, W. Va. 



Helderberg formation, Keyser member, Cumberland. 



Figs. 10-13. HIPPARIOXYX PROXIMI T S Vanuxem 333 



10, 11. Dorsal and ventral valves. 



12, 13. Interior ventral and dorsal valves. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Fig. 14. CHOXETES ROWEI Schuchert n. sp 336 



Ventral valve. Oriskany formation, Ridgely member, Miller's Spring, 

 near Cumberland. 



Fig. 15. CHOXETES HTJDSOXICUS Clarke 337 



Ventral valve. The umbo is cracked. Oriskany formation, Ridgely 

 member, Winchester road. 



Fig. 16. CHOXETES SUBACUTIRADIATUS Schuchert n. sp 335 



Ventral valve. Helderberg formation, New Scotland member, Miller's 

 Spring, near Cumberland. 



Figs. 17-19. CHOXETES JERSEYEXSIS Weller 338 



17. Ventral valve of a young individual, Tonoloway. 

 18, 19. Ventral and dorsal valves, Flintstone. 



Helderberg formation, Keyser member. 



Fig. 20. CHOXETES JERSEYEXSIS VAR. SPIXOSUS Maynard n. var 339 



Ventral valve. Helderberg formation, Keyser member, Hancock. 



Fig. 21. AXOPLIA HELDERBERGI^ Schuchert n. sp 340 



Ventral valve. X 3. The median furrow is due to a fracture. The 

 shell is uniformly convex. Helderberg formation, New Scotland 

 member, 21st Bridge. 



Figs. 22-24. AXOPLIA XUCLEATA (Hall) 340 



22. Exterior of dorsal valve. X 3. 



23. Interior of dorsal valve. X 2. 



24. Cardinal view of the internal cast of the ventral valve. 



Oriskany formation, New York. 



