PLATE XIX. 
Fig. 1. 
Figs. 2, 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. 
Fig. 8. 
Figs. 9- 
Fig. 12. 
Figs. 13- 
Figs. 16- 
Figs. 21- 
Fig. 24. 
Figs. 26, 
Fig. 28. 
Fig. 29. 
Fig. 30. 
Fig. 25. 
Fig. 31. 
Leiopteria Dekayi. 
Pag-e 164. 
See Plates 20 and 88. 
A small left valve. The specimen shows no indications of rays such as are represented in the 
figure. Hamilton group. Cooperstown, N. Y. 
Actinopteria Boydi. 
Page 113. 
See Plate 84. 
3. Two left valves preserving the surface ornamentation. 
Hamilton group. Schoharie Go., N. Y. 
A left valve. 
A small left valve. 
Hamilton group. Jefferson, Schoharie Co., N. Y. 
A right valve with an unusually extended wing-. 
Hamilton group. Fvltonham, Schoharie Co., N. Y. 
The exterior of a right valve, as obtained from a gutta-percha impression of the natural mould, 
showing the spinous processes of the lamellae. 
Hamilton group. Fultonliam, Schoharie Co., N. Y. 
The preceding figures represent the forms described as Avicula quadi’ula, Conrad. 
A small left valve. The ear should be represented as somewhat oblique. 
Hamilton group. Jefferson, Schoharie Co., N. Y. 
-11. Three left valves showing gradation in size and slight differences in form and surface char¬ 
acters. 
A small rig-lit valve enlarged to two diameters. Another figure of this specimen is given of the 
natural size in fig. 17, pi. 84. 
Hamilton group. Hamilton, Madison Co., N. Y. 
-15. Three left valves differing slightly in form and surface ornaments. 
Hamilton group. Schoharie Co., N. Y. 
-20. A series of left valves representing the type A. Boydi of Conrad. 
-23. Right valves associated with and corresponding to the preceding. 
Two individuals, each retaining both valves in contact. 
Hamilton group. Figs. 16 and 17 are from Schoharie county; the others are from 
Onondaga and Madison counties, N. Y. 
27. Two large left valves. 
Hamilton group. Cazenovia, Madison Co., N. Y. 
The right valve of the specimen, fig. 26, showing the comparative size of the two valve's, 
Cardinal view of the preceding. Another view of the left valve is given on plate 84, fig. 16. 
A right valve showing unusually fine concentric striae. 
Hamilton group. Cazenovia, N. Y. 
Actinopteria subdecussata. 
Page 110. 
See Plate 17. 
A left-valve showing the characters as preserved in a coarse shale. 
Hamilton group. Cazenovia, N. Y. 
Actinopteria perobliqua. 
Page 116. 
See Plate 84. 
The right valve of the specimen described. The left valve of this specimen is figured on plate 84, 
fig. 14. Hamilton group. Cazenovia, N. Y. 
