Spirifer Williamsi, Hall. 

 Page 356. 

 Figs. 17, 18, 19. Dorsal, cardinal and ventral views of a large example, show- 

 ing the low, coarse and sparse plication of the fold and sinus. 

 Chemung group . Allegany county, N. Y. 



Spibifer mucronatus, Conrad, var., posterus, Hall. 



Page 356. 



Fig. 20. An internal cast of the pedicle- valve, showing the impression of the 



muscular area. 

 Fig. 21. Internal cast of a brachial valve. 



Fig. 22. Exterior of a brachial valve, showing the lamellose surface and ex- 

 tended cardinal extremities. 

 Fig. 23. Internal cast of a brachial valve. 



Fig. 24. The central portion of the interior of a brachial valve, enlarged. 

 Chemung group. Tompkins County, N. Y. 



Spirifer Newberry i, Hall. 

 Page 357. 

 Fig. 25. The exterior of the brachial valve. 

 Fig. 26. An enlargement of the surface. 

 Waverly group. Ohio. 



Spirifer disjunctus, Sowerby, var. sulcifee, Hall. 

 Page 356. 

 Fig. 27. The internal cast of a brachial valve ; showing the sulcus on the pli- 

 cated fold. 

 Chemung group. Near Olean, N. Y. 



Cyrtia radians, Hall. 



Page 357. 



Figs. 28, 29. Cardinal and profile views of the original specimen. The cen- 

 tral cardinal area of two examples, showing the direct circular foramen 

 and elongate foraminal groove. 

 Clinton group. Rochester, N. Y. 



387 



