PLATE LXVI—Continued. 
Fig-. 20. 
Fig-. 21. 
Fig. 22. 
Fig. 23. 
Fig. 24. 
Fig. 25. 
Fig. 26. 
Fig. 27. 
Fig. 28. 
Fig. 29. 
Fig. 30. 
Fig. 31. 
Fig. 32. 
Fig. 33. 
Fig. 34. 
Fig. 35. 
Fig. 36. 
Fig. 37. 
Fig. 38. 
Fig. 39. 
Bactropora granistriata. 
Page 193. 
A fragment, natural size. 
An enlargement from the preceding, showing the pointed, striated base, and the form and disposi¬ 
tion of the cell apertures. (X 6.) 
A still farther enlargement, showing more distinctly the character of the cell apertures and the 
intermediate surface. (X 18.) 
Hamilton group. Darien Centre, Genesee county, N. Y. 
Glauconome carinata. 
Page 273. 
Two fragments, natural size. 
An enlargement from the non-celluliferous face, showing the sharp ridges and the mode of 
branching. (X 6.) 
Hamilton group. Fall-brook, four miles east of Canandaigua lake, N. Y. 
Ptilopora nodosa. 
Page 285. 
An enlargement, showing the intervals between the lateral branches, the form and disposition of 
the cell apertures, and the nodes on the midrib and branches. 
Hamilton group. Near Alden, N. Y. 
Ptilopora infreqqens. 
Page 284. 
A fragment of a frond, natural size. 
An enlargement from the non-celluliferous face of the preceding, showing the manner of growth 
and alternating striations of the surface. (X 6.) 
A fragment, natural size. 
An enlargement from the preceding. (X 6.) 
Hamilton group. Western New York. 
Ptilopora striata. 
Page 283. 
A fragment, natural size. 
A specimen, natural size, restored, showing the general appearance and mode of growth. 
An enlargement from the non-celluliferous face of a specimen, showing the appearance of the 
midrib, lateral branches and dissepiments, and the form of the fenestrules. (X 6.) 
An enlargement from the celluliferous face, showing the form and disposition of the cell apertures. 
(X 6.) 
Hamilton group. Moscow, Livingston county, N. Y.,and West Williams, Ontario. 
Fenestrapora biperforata. 
Page 28C. 
A fragment, natural size. 
An enlargement from the non-celluliferous face of a frond, showing the comparative size of the 
branches and dissepiments, the form of the fenestrules and the perforations of the branches. 
An enlargement from the celluliferous face ; the lower portion of the figure shows the perforated 
summit of the carinse; in the upper portion the carinse are broken away, showing the form 
and arrangement of the cell apertures. (X 6.) 
A still farther enlargement of the summit of the carinse, showing more distinctly the oval and 
triangular perforations. (X IS.) 
An enlargement of the non-celluliferous face, showing triangular perforations, the remainder of 
the branch being smooth. (X 18.) 
An enlargement from another specimen, showing triangular perforations, short striations and 
comparatively conspicuous nodes. (X 18.) 
Hamilton group. Moscow, Livingston county, N. Y. 
