PLATE LXVII 



PAGE 



Figs. 1-3. REXSSEL.ERIA (BEACHIA) PROAVITA Schuchert n. sp 385 



1. Ventral valve. X 1%. 



2, 3. Dorsal and side views of another specimen. X 1%. 



Helderberg formation, Keyser member, Pinto. 



Figs. 4-6. RENSSEIJERIA (BEACHIA) CUMBEBLAXDM: (Hall) 386 



Dorsal, ventral, and side views. Oriskany formation, Ridgely mem- 

 ber, Cumberland. 



Figs. 7-15. RENSSEL/ERIA (BEACHIA) SUESSANA (Hall) 387 



7, 8. Dorsal and side views of a small specimen. 



9, 10. Same of an average specimen. 



11. Dorsal view of an elongate specimen. 



12, 13. Dorsal and side views of a large specimen. 



14. Interior of dorsal valve. 



15. Longitudinal section of valves showing crura and appendages. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Fig. 16. RENSSEL.ERIA (BEACHIA) SUESSAXA VAR. IMMATURA Schuchert n. 



var 388 



Dorsal valve. X 1%. Oriskany formation, Shriver member, Cash 

 Valley, Cumberland. 



Figs. 17-19. RENSSEL^RIA (BEACHIA) OVALIS (Hall) 389 



17, 18. Ventral and side views. 

 19. Internal cast of ventral valve. 



Oriskany formation, New York. 



Figs. 20-24. ORISKANIA LUCERNA Schuchert n. sp 390 



20-22. Dorsal, ventral, and side views. 



23, 24. Interior of ventral and dorsal valves. X 2. 



Oriskany formation, Ridgely member, Cumberland. 



Fig. 25. TROPIDOLEPTUS CARINATTJS (Conrad) 390 



Ventral valve. Oriskany formation, Ridgely member, Cumberland. 



Figs. 26-28. ATRYPA RETICULARIS (Linne) 392 



26, 27. Dorsal and side views. 

 28. Interior of ventral valve. 



New Scotland formation, New York. 



53 



