PLATE 33. 



Pago 



Figs. 1 - 21. Spirifeka fimbriata 214 



1. An imi>erfect dorsal valve of this siwcies, from the Oriskany sandstone. 



2. A view of an imperfect ventral valve of this species. 



8. The cast of a ventral valve, showing the muscular impression. 



4. A view of a cast of a dorsjil valve. This, and tlie two preceding figures, are from speci- 



mens found in the Schoharie grit. 



5, 6. Dorsal and ventral views of a small individual, from the Corniferons limestone. 

 7. A dorsal view of an individual of medium size, from the Corniferous limestone. 



8-11. Profile, dorsal, ventral and front views of a full grown individual, from the Corniferous 



limestone. 

 12, IH. Dorsal and ventral views of a small individual. 



14. Cardinal view of a short individual of this species. 



15. A ventral view of another specimen which preserves the fine .setiform spires of the surface. 

 16 - 19. Profile, front, dorsal and ventral views of a large sized specimen. Figures 12 - 19 



are from specimens from the soft shales of the Uamilton group. 



20. A cardinal view of a cast of this species, from the Hamilton group, Hardy county, Va. 



21. Enlargement of the surface of specimen fig. 18, showing the pustulose markings. 



Pigs. 22 - 30. Spirifera strBUMBONA 234 



22. 23. Dorsal and profile views of a specimen of this species. 

 24. Dorsal view of another individual. 



25 - 29. Dorsal, ventral, profile, cardinal and front views of a large and rather gibbous specimen. 

 80. Enlargement of the surface, showing the small pits that result frorti a partial exfoliation of 



the shell. These figures are from specimens occurring in the limestones of the Marcellus 



shales. 



Figs. 31 - 35. Spirifera PR.a;HATURA 250 



31. A ventral valve of a small individual. 



82. A larger dorsal valve, showing the pustules of the surface. This, and the preceding figure 



are from New York specimens. 



83. Cast of another dorsal valve, showing the impression of the median septum. 



84. View of the cast of a ventral valve. 



85. Ca.st of ventral valve of another individual, having a much larger rostral ^avity. This, and 



the two preceding figures, are from specimens occurring near Meadville, Pa. 



