PLATE XLII—Continued. 
Fenestella (Polypora) l^evinodata. 
Page 169. 
A fragment of the non-celluliferous face of a frond, natural size. 
An enlargement of a portion of fig. 12. The branches are angular, sometimes carinated, very 
irregular and with comparatively strong, irregularly disposed nodes. (X 6.) 
An enlargement of another portion of fig. 12. The branches are regular; branches and dissepi¬ 
ments angular and carinated, with minute nodes on the earination of the branch opposite the 
dissepiments. (X 6.) 
An enlargement from the celluliferous face of a frond. The surface of the branch at the right is 
removed, showing the cellular interior and the form and arrangement of the cells. The con¬ 
tiguous branch has the surface partially worn away, showing the apertures of the cells very 
much enlarged, and but partially retaining their circular form The remaining branches are 
in a perfect condition and show the form and arrangement of the cell apertures, the granules 
between the apertures, and, on the branch at the left, the comparatively strong ridges sepa¬ 
rating the longitudinal ranges of cell apertures. (X 6.) 
Upper Helderberg group. Falls of the Ohio river. 
FeNESTELLA JBISERIATA. 
Page 113. 
Fig. 16. A fragment of the non-celluliferous face of a frond, natural size. 
Fig. 17. An enlargement of a portion of fig. 16, showing the comparative size and character of the branches 
and dissepiments, and the form of the fenestrules. (X 6.) 
Fig. 18. An enlargement from the celluliferous face of a frond; the branches and dissepiments are angular 
and carinated; the cell apertures in two ranges. (X 6.) 
Upper Helderberg group. Cherry Valley, N. Y. 
Fenestella peculiaris. 
Page 113. 
Fig. 19. A fragment of the non-celluliferous face of a specimen, natural size. 
Fig. 20. An enlargement of a portion of fig. 19. The surface has been macerated and the external 
markings are obsolete, the branches appearing flat. (X 6.) 
Fig. 21. An enlargement of another portion of fig. 19. The upper portion is well preserved, showing the 
nodes as the most prominent feature. The branches of the lower part of the figure are in the 
same condition as those of fig. 20. (X 6.) 
Upper Helderberg group. Near Caledonia, N. Y. 
Fig. 12. 
Fig. 13. 
Fig. 14. 
Fig. 15. 
