xi/: 



PLATE XXIX— Continued. 



Inteapora PUTEOLATA. ,1 /. .1 .-^n 



^nii<iilMn Imnotiii '>»ll .••l*'* in^nslilnllM • ••ill Page 97. ''A L' .'ji'-I 



"Figi. 18-22. Frag-ments, natural sizo, shuwiiiff the ordinafj' vnriatidiis in form of ditlV-rent fi-onds 



'tSgi 23. An enlarg:ement of a portion of the siirface of a frond, showing circular cell aperlui-es ( the intet-^ 

 apertural pits on a portion of the figure are obsolete. (X 18.) ' '' '••'•iiil'i'"p 



Fig. 24. An enlargement of a part of a frond, showing the form and tnod^ ' oT"b}fiireation, the arrange- 

 ment of the cell ajiertures, the interaiiertural j)it,s, and the non-celluliferous space at the mar- 

 gin ha\-ing indi.stinct pits arr»ng*d in oblique rows, resembling oblique striations. 



Fig. 2.'>. A transverse section of one-half of a frond, enlarged, showing the mesotheca and the upright 

 l)ortion of the cell tubes. (X 6.) .' :)>! / .1 .jil 



Fi^. 36. An enlargement, to eighteen diametei'H, of a poKion of the sj^ecimen, fig.^tfi'omneav'tbe mar-^ 

 gin, showing more distinctly the character of the«eH npertures and intermediate pits and the 

 non-cellalifei'ons striated margin. • ■li .: ■ii ; ,i ,,,:„/ J.  '• ' 



Upper Helderbei-g gi-oup. fWls of tke Ohio Hver.  »i»l sdt 



-.,1 1 I" Ji.-iii-'ai *. ' ^1. -'til .  -I. I !■ ' ' ' t 



(.;< X) R-.i.iif..|« iir. Stictopora rhomboidea. 



Pago 95. ■*' * 



Fig. 27. A fragment, natural size. 



Rg. 28. The surface, enlarged, showing the form and an-angenient of the cell apertures. ( X 6 ) 



Upper Helderberg group. Near Le lUty, N. Y. 



Coscinotrypa cribriformis, vai-. carinata. 



Page as. 



„. _ . , , . See Plate 33. iimv""? .U .01 .« .a%,i^ 



Fig. 29. A fragment, natural size. , .. , „, ... 



Fig. 30. A transvei-se section, natural size. ■, . , -  



Fi^. 31-3^<. Fragments, natural size, showing the coinuion \'ariatious of the different ^^^mda.^n tile ,aize.,(rf'i 



the fenestrules and general appearance of the surface. . ,, i,,., ",, , ,1,1 



Fig. 34. A portion of the surface of a frond, enlarged,, showing alternating and imbric|»tin^,c^ll apertui-es. 



Fig. 35. An enlargement, sho.ving one of the feneatrules, and the oi'dinai:y fomiaii(i arrangement of the 



denticulated cell apertui-es. (X 6.) i 



*•.•... Upper Helderberg gn)iy>,.i^atf«,</;tte,(?A^<>n,«!ir. .^ f-nsvaiimJ A .81 .^i^ 



Stictopora perarct^, Uall. 



PaseM. 



Fig. 36. A fragment, natural size. , 1// ;ii) ;ai A;i(VJOKi<i;tM 



Kg. 37. The surface enlargeil, showing the form an<l arrangement of the cell apertures. (X 18.) 



Upper Helderberg group. Onoiidaga Valley, N. Y. 



.^- ■■:j;i'(  ' 



Uiujaa .Jii<>ii]^«il A .dl .yV 

 u'lKlimuA .VI -T^n 



