PLATE XVI. 



(Figures 1-16, 18-23, 24-30, 32-44 by R. P. Whitfield ; 17, 31 by F. B. Meek; 23 copy.) 



Legend. T>. Deltidium, pedicle- valve. j. Cardinal process. 



C. Deltidium, brachial valve. a. Anterior adductors, 



st. Cardinal tubes. a'. Posterior adductors, 



t. Teeth. v. Anterior diductors. 



b. Dental sockets. r'. Posterior diductors. 



s. Septum. V. Brachial ridgpes. 



Genus CHONETES, Fischer de Waldheim. 



(See Plate XVb.) 

 Page 303. 



Chonetes cornuta, Hall. 



Fig-. 1. A view of the pedicle-valve. X 2. 



Clinton group. Sodii,s Bay, N. Y. 



Chonetes setigera, Hall. 



Fig. 2. A view of the pedicle-valve. X 2. 



Waverly gi'oup. Penfielcl, Ohio. 

 Fig. 5. Pedicle-valve of a larger specimen with finer strias. X 2. 

 Fig. 19. An enlargement of the surface striae of this specimen. 



Mai-cellus shales. Near Caledonia, N. Y. 



Chonetes scitui-a, Hall. 



(^)Fig. 3. A pedicle-valve, with somewhat more circular outline and longer cardinal spines than usual. X 2. 



Fig. 4. A view of the brachial valve ; showing the cardinal area and deltidium. 



Fig. 27. The interior of a brachial valve ; showing the structure of the cai'dinal pi-ocess and the faint 



brachial ridges. X 2. 

 Fig. 32. The interior of the pedicle-valve ; showing the cardinal area and teeth. X 2. 



Hamilton group. Canandaigua Lake, N. Y. ■ 



Fig. 40. An enlargement of the cardinal portion of the valves; showing the hollow spines and the curving 

 coui-se of the spine-tubes thi'ough the substance of the cardinal area of the pedicle-valve. X 8. 

 Hamilton group. Western New York. 

 Fig. 44. An internal cast of the pedicle-valve, retaining the tilling of the spine-tubes and showing their 

 convergence toward the beak before reaching the upper margin of the area. X 8. 

 Chemung gi'oup. Cattaraugus county, N. Y. 



Chonetes mucronata, Hall. 



Fig. 6. A pedicle-valve with very coarse plications and apparently destitute of spines. X 2. 

 Fig. 7. A pedicle-valve with long, extremely divergent spines. X 2. 

 Marcellus shales. West Avon, N. Y. 



Chonetes acutiradiata, Hall. 



Fig. 8. The pedicle-valve. 



Corniferous limestone. Williamsville, N. Y. 



Chonetes Logani, Norwood and Pratten, var. Aurora, Hall. 



Fig. 9. Pedicle-valve, enlarged to show the tine concentric strise. X 3. 

 Fig. 18. An enlargement of the sui'face. 



Tally limestone. TuUy, N. Y. 



