PLATE XLVI. 



Fenestella curvuunctura. 



Page 107. 



Fig'. 1. A. figure, natui'al size, showing the mode of gi-owth and the disposition of the bi-anches and dis- 

 sejiiments. 



Fig. 2. An enlargement from the preceding, showing more distinctly the appeai'ance of the branches and 

 the curved dissepiments. (X 6 ) 



Fig. 3. An enlargement from the cellulifei-ous face, showing the foi-m and disposition of the cell aper- 

 tures. (X 6.) 



Fig. 4. An enlarfjement of a lateral view of a branch, showing the oblique dissepiments, and the noiies 

 on the middle of the branch. (X 6.) 



Fig. 5. An enlargement of a ti-ansvei-se section of the branches. (X 6.) 

 Upper Helderberg gi-oup. Mills of the Ohio rirser. 



rE.\E.STELI.A (PoLYI'OKa) KOBUSTA. 



I'age 186. 



See Plates ;i4, 37, 39 and 43. 



Fig. 6. An enlargement fi-ora the non-celluliferous face, showing very slender dissepiments, and both 

 angular and striated V>riiiiches. (X 6.) 



Upper HelderlxM-g gn>up Walpule, Ontario, Canada. 



Fenestella [Ptiloporina ?] confertii>oka. 



Pajro 1(W. , 



Fig. 7. A fragment, natural size. 

 Fig. 8. An enlargement from a portion of the preceding, showing the onlinary slender branches and one 



of the larger braiu;hes. ( X tt- / 

 Fig. 9. An enlargement from the celluliferous face, showing the circular, crowded cell apertures, and 



occa.sional larger apertures. (X 6.) 

 Pig. 10. An enlar^'ement of a trau.iverse section of sevei-al bi-anches. (X ti.) 

 Fig. II. An enlargement of a lateral view of a bi-anch, showing the cell apertures and a section of the 



dissepiments. (X <5). See figs. 17-21. 



Upi>er Helderberg group. fWi* of the Ohio rivKr. 



Fene.stem,a sinqularitas. 



Pag« 114. 

 Fig, 12. A fragment, natural size. 



Fig. 13. An enlargement from the pi-eceding, showing more distinctly the appearance of the branches and 

 dis.<<epiments, and the conspicuous no<ies below the bifurcations (X 6.) 



Fig. X4. An enlargement from the cellulifei-ou.s face, shoM-ing the obtusely angular branches, prominent 

 nodes, and the disposition of the cell apertui-es. (X ').) 



Fig. 15. An enlargement of a transvei-se seittinn of several branches. (X 0.) 



Pig. 16. An enlargement of a hiteral view of a bianch. showing' sectiou.s of the dissepiments, the cell 

 apertures and the distant notles im the two surfaces. (X 6.) 

 Upper Helderlxii-g group. Falls of the Ohio river. 



Fenestella [Ptilopori.na ?j confertipora. 



_. „ , Page 108. 



Fig. 17. A fi-agment, natural size. 



Fig. 18. An enlargement from thi- preceding, showing more distinctly the form and disposition of the 



branches and dissepiments. (X ti.) 

 Fig. 19. An enlargement from the celluliferous face of a specimen moi-e macerated than fig. 9. (X tJ.) 

 Fig. 20. An enlargement of a transverse section of branches. (X <i.) 

 Fig 21. An enlargement of a lateral view of a branch, showing transverse sections of dissepiments, and 



the very prominent nodes upon the celluliferous face. (X 6). See figures 7-11. 

 Upper Helderberg group. Falls of the Ohio river. 



