PLATE XLII. 



Fenestella (Polypora) carinella. 



Page 153. 

 Fig. 1. An enlargement from the celluliferous face, showing the character and comparative size of 

 the branches and dissepiments, the form and arraiigreraent of the cell apertures, and the long- 

 itudinal carinre separating the ranges of apertures. (X t>.) 

 Fig. 2. An enlargement from the non-cellaliferou.s face of the frond, showing the compai-ative size and 

 character of the branches an<l dissepiments, and the form of the fenestrules. (X 6.) 

 Upper Helderberg group. Near Buffalo, N. Y. 



Fexestela (Polypora) elonoata. 



Fig. 3. An enlargement from the nou-celluliferons face of a frond, showing the comparative size and 

 character of the branches and dissepiments and the foi-m of the fenestrules. (X 6.) 



Fig. 4. An enlargement from the celluliferous face of a frond, showing the form and arrangement of 

 the cell apertures, the continuous strise between the ranges of apertures, and the intermedi- 

 ate inten-upted striie. The surface of the branch at the right is broken away, showing the 

 fonn and ari-angement of the cells (X •>■) 



Upjier Helderberg group. Oiumdaga Valley, N. V. 



Fenestella (Polypora) celsipora. 



Page ISU. 

 See Plate 41. 



Fig. 5. The non-celluliferous face of a frond, natui-al size 



Fig. 6. An enlargement of a portion of fig. .'). The bran<'hes have from three to five stnations, and are 

 from two to four times the width of the dissepiments, and fi-om two to three times the width of 

 the fenestrules. (X <>•) 



Pig. 7. An enlargepient of another jKirtion of flg. 5. The bi-ancht>s are moro slender than in the pre- 

 ceding figure, the f<!ne.sti-ules are sub-quadrangular, and their width is equal to or greater 

 than that of the brunches. (X 6.) 



Fig. 8. An enlargement from the celluliferous face of a frond, showing the comparative size of the branches 

 and dissi^piments, the form and aiTangement of the cell apertures, the carinie separating the 

 ranges of apertures, when more than two ranges occur, and appearing as a central carina 

 where only two ranges occur. (X 6.) 



Fig. 9. A fragment of the non-celluliferous face of a frond, natural size. 



Fig. 10. An enlargement of a portion of fig. 9, showing the comparative size and character of the branches 

 and dissepiments, and the quadrangular form of the fenestrules. (X 6.) 

 Upper Helderberg group. WaXpole, Ontario, Caiuula. 



Fenestella verrucosa. 



Page no. 



See Plate 46. 



Fig. 11. An enlargement from the non-celluliferous face of a frond, showing the comparative size and 



character of the branches and dissepiments, and the irregulai-ly nodulose surface. (X 6.) 



Upper Helderberg group. Palls of the Ohio river. 



