PLATE LX 



PAGE 



Figs. 1-3. SCHUCHERTELLA FROLiFicA Schuchert n. sp . . 4 327 



1. Ventral valve. 



2. Interior of dorsal valve. 



3. Two small overlapping ventral interiors. 



Helderberg formation, Keyser member, Keyser, W. Va. 



Figs. 4-9. SCHUCHERTELLA WOOLWORTHANA (Hall) 328 



4. Dorsal view. 



5. Ventral valve. 



6. Interior of a large ventral valve. 



New Scotland formation, New York. 



7. Dorsal valve. Helderberg formation. New Scotland member, 



Cedar Cliff, W. Va. 



8. 9. Internal cast of ventral and dorsal valves. New Scotland forma- 



tion, New York. 



Figs. 10-12. SCHUCHERTELLA BECRAFTEXSIS (Clarke) 329 



10, 11. Two dorsal valves. 

 12. Interior of ventral valve. 



Oriskany formation, New York. 



Figs. 13-16. SCHUCHERTELLA DECKERENSIS (Weller) 329 



13, 14. Ventral valves. 



15. Cardinal view. 



16. Dorsal valve. 



Helderberg formation, Keyser member, Keyser, W. Va. 



