PLATE 11. 



Fenestella (Unitrypa) scalaris. 



Figs. 1-11. 



Fig. 1. A fragment of the carinas and scalte ; natural size. 



Fig. 2. An enlargement showing a row of prominent nodes along the 



middle of the branch and a row of granules on each side. 6 x. 

 Fig. 3. An enlargement showing the lateral rows of nodes much stronger 



than in fig. 2. 6 x. 

 Fig. 4. An enlargement showing two rows of nodes on each branch, the 



middle of the branch a little depressed. 6 x. 

 Fig. 5. An enlargement of the summits of the carinee and scalee, showing 



nodes on the carinas. 6 x. 

 Fig. 6. An enlargement showing very thin carinas and scalfe. 6 x. 

 Fig. 7. An enlargement showing the under side of the carinte and scalee. 



6 X. 

 Figs. 8 and 9. Transverse sections of different fronds. 6 x. 

 Fig. 10. A transverse section further enlarged, showing the rhomboidal 



form of the branches, their structure, the dissepiments and 



scalfe, and the form of the expanded portion of the carina. 



18 X, 

 Fig. 11. A translucent longitudinal section on glass, showing the structure 



of the branches and dissepiments, greatly enlarged. 

 Formation and locality. — Hamilton group ; Bellona, Yates county, 



N. Y. 



Fenestella (Polypora) multiplex. 

 Figs. 12-16. 



Fenestella (Polypora) multiplex, Hall. Eeport of State Geologist for 



1886, page 66. 



Fig. 12. A fragment, showing the celluliferous face, natural size. 



Fig. 13. An enlargement from the celluliferous face, showing the form 

 and disposition of the cell apertures, and the striae or ridges 

 between the ranges of apertures. 6 x. 



Fig. 14. An enlargement, showing the angular branches of the non-cellu- 

 liferous face, connected by slender depressed dissepiments. 



Figs. 15, 16. Transverse sections from different fronds, showing the varia- 

 tion in the form of the branches. 6 x. 

 Formation and locality. — Hamilton group; Moscow, Livingston 

 county, N. Y. 



