PLATE I>XVI— ConUnneil. 



Bactropou,v OUANISTRIATA. 

 Page 193. 

 Fi^. 30. A frapnent, natural size. 



Pig. 21. An enlargement from the preceding, showing the pointed, striated base, and the foi-m and disposi- 

 tion of the cell ajMirtures. (X 6.) 

 Fig. 22. A still farther enlargiMiient, showing more distinctly the character of the cell apei-tures and the 

 intermediate siu-face. (X 18.) 



Hamilton group. Darien Centre, Oenesee county, N. Y. 



Glauconome carinata. 



Paso 273. 

 Fig. 23. Two fragments, natural size. 



Fig. 24. An enlargement from the non-celluliferous face, showing the sharp ridges and the mode of 

 branching. (X 6.) 



Hamilton group. Fall-brook, four miles ea^l of Canandaigua lake, N. Y. 



Ptilopora nodosa. 



Pago 285. 

 Fig. 25. An enlargement, showing the intervals between the lateral branches,'the form and disposition of 

 the cell apertures, and the nodes on the midrib a"d bi-anches. 

 Hamilton group. Near Alden, N. Y. 



Ptilopora lnfrequens. 



Page 284. 

 Fig. 2G. A fragment of a frond, natural size. 

 Fig. 27. An enlargement from the non-celluliferous face of the preceding, showing the manner of growth 



and alternating striations of the surface. (X 6.) 

 Fig. 28. A fragment, natural size. 

 Fig. 29. An enlarjjemfnt from the pi'eceding. (X 6.) 



Hamilton group. Western New Yar/c. 



Ptilopora striata. 



Page 283. 

 Pig. 30. A fragment, natural size. 



Fig. 31. A specimen, natural size, i-estoi-ed, showing the general appearance and mode of growth. 

 Fig. 32. An enlargement from the non-celluliferous face of a specimen, showing the appearance of the 



midi-ib, lateral branches and dissepiments, and the form of the fenestrules. (X 6.) 

 Fig. 33. An enlargement from the cellulifei-ous face, showing the form and disposition of the cell apertui-es. 



(X 6.) 



Hamilton group. Moscow, Livingston county, N. Y.,and West WUliams, Ontario. 



Fenestrapora biperforata. 



Page 286. 

 Fig. 34. A fragment, natural size. 

 Fig. 35. An enlargement from the non-celluliferous face of a fi-ond, showing the comx)arative size of the 



branches and dissepiments, the form of the fenestrales and the i)erforations of the branches. 

 Fig. 36. An enlargement from the cellulifei-ous face ; the lower portion of the figure shows the pei-forateil 



summit of the carina ; in the upper portion the carinse are broken away, showing the form 



and arrangement of the cell apertures. (X 6.) 

 Fig. 37. A still farther enlargement of the summit of the carinie, showing moi-e distinctly the oval and 



triangular perforations. (X 18.) 

 Fig. 38. An enlargement of the non-celluliferous face, showing triangular perforations, the remainder of 



the branch being smooth. (X 18.) 

 Pig. 89. An enlargement from another specimen, showing ti-iangular perforations, short sti-iations and 



comparatively conspicuous nodes. (X 18.) 



Hamilton group. Moscow, Livingston county,',N. Y. 



