PLATE LXIII 



PAGE 



Figs. 1-4. STEXOCHISMA DECKEREXSIS (Weller) 349 



1-3. Ventral, side, and dorsal views. 



4. Dorsal view of a smaller specimen. 



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



Figs. 5, 6. CAMAKOTCECHIA ? ALTIPLICATA (Hall) 351 



5. View of ventral valve. 



6. Side view of same. 



New Scotland formation, New York. 



Figs. 7, 8. CAMAROTCECHIA ORISKANIA Rowe n. sp 351 



Dorsal and side views of shell. Oriskany formation, Ridgely member, 

 Cumberland. 



Figs. 9, 10. CAMAROTCECHIA ? LAMELLATA (Hall) 352 



Dorsal and ventral views of shells. Cobleskill formation, New York. 



Figs. 11-14. CAMAROTCECHIA LITCHFIELDEXSIS Schuchert 353 



Anterior, side, ventral, and dorsal views. Helderberg formation, 

 Keyser member, Cookerly. 



Figs. 15, 16. CAMAROTCECHIA GIGANTEA Maynard n. sp 354 



Dorsal and ventral views. Helderberg formation, Keyser member, 

 Devil's Backbone. 



Figs. 17-19. CAMAROTCECHIA (PLETHORHYNCHA) CAMPBELLANA (Hall) .... 354 

 Ventral, anterior, and side views. New Scotland formation, New York. 



Figs. 20, 21. CAMAROTCECHIA (PLETHORHYNCHA) PR.ESPECIOSA Schuchert 



n. sp 355 



20. View of a dorsal valve. 



21. Side view of shell. 



Helderberg formation, Becraft member, near Covington, Va. 



Figs. 22-27. CAMAROTCECHIA (PLETHORHYNCHA) SPECIOSA (Hall) 356 



22. 23. Dorsal and side views of a medium sized specimen. 

 24, 25. Dorsal and side views of a large example. 



26, 27. Interior of ventral and dorsal valves. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



