PLATE LXXIII 



PAGE 



Figs. 1, 2. TREMATOSPIRA SIMPLEX Hall ? 427 



Dorsal and ventral views. X 2. Helderberg formation, New Scotland 

 member, Devil's Backbone. 



Figs. 3, 4. TREMATOSPIRA MULTISTRIATA (Hall) 428 



Dorsal and ventral views. Helderberg formation, New Scotland mem- 

 ber, Corriganville. 



Figs. 5-7. TREMATOSPIRA DEWEYI (Hall) 429 



Dorsal, ventral and side views. New Scotland formation, New York. 



Figs. 8, 9. TREMATOSPIRA EQUISTRIATA Hall and Clarke 430 



Dorsal and ventral views. Helderberg formation, New Scotland mem- 

 ber, Corriganville. 



Figs. 10-12. NUCLEOSPIRA VENTRICOSA (Hall) 430 



Dorsal, ventral, and side views. New Scotland formation, New York. 



Figs. 13, 14. NUCLEOSPIRA ELEGANS Hall 431 



Dorsal and ventral views. The sinus in the dorsal valve is drawn too 

 angularly. X 1%. Helderberg formation, New Scotland mem- 

 ber, Corriganville. 



Figs. 15-17. NUCLEOSPIRA SWARTZI Maynard n. sp 432 



Ventral, dorsal and side views. Helderberg formation, Keyser mem- 

 ber, Keyser, W. Va. 



Figs. 18, 19. ANOPLOTHECA CONCAVA (Hall) 434 



*/* Dorsal and ventral views. X 3. Helderberg formation, New Scotland 



I member, Corriganville. 



Figs. 20, 21. ANOPLOTHECA CONCAVA VAR. TONOLOWAYENSIS Swartz n. var.. 434 

 Dorsal and ventral views. X 2. Helderberg formation, Keyser mem- 

 ber, Tonoloway. 



Figs. 22, 23. ANOPLOTHECA EQUISTRIATA Schuchert n. sp 435 



Dorsal and ventral views. X 2. Oriskany formation, Ridgely mem- 

 ber, Cumberland. 



Figs. 24-26. ANOPLOTHECA DICHTOMA (Hall) 435 



24, 25. Dorsal and ventral views. 



26. Anterior view to show concave dorsal valve. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Figs. 27, 28. ANOPLOTHECA (LEPTOCCELIA) FIMBRIATA (Hall) 436 



Dorsal and ventral views. Oriskany formation, Ridgely member, Cum- 

 berland. (After Hall.) 



Figs. 29-33. ANOPLOTHECA (LEPTOCCELIA) FLABELLITES (Conrad) 438 



29-31. Dorsal, ventral, and side views. 

 32, 33. Interior ventral and dorsal valves. 



Oriskany formation, Ridgely member, Cumberland. (After 

 Hall.) 



Figs. 34-36. WHITFIELDELLA ( ?) PROSSERI Grabau 439 



Ventral, dorsal, and side views. Helderberg formation, Cherry Run, 

 W. Va. 



Figs. 37-40. WHITFIELDELLA ( ?) NUCLEOLATA Hall 441 



37. Dorsal view of small specimen. 

 38-40. Ventral, dorsal, and side views. 



Cobleskill formation, New York. 



Figs. 41, 42. WHITFIELDELLA (?) MINUTA Maynard n. sp 442 



Dorsal and ventral views. X 5. Helderberg formation, Keyser mem- 

 ber, Round Top. 



Figs. 43-46. MERISTELLA PR.ENUNTIA Schuchert n. sp 443 



43. Dorsal view of specimen with strong median fold. 

 44-46. Ventral valves showing differences in development of sinuses. 

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



