PLATE LXI— Continued. 



StICI'OPOKA SINU08A. 

 Page 217. 

 Fijf. 17. An enlargement, showinif the form iiiul dispo-sition of tlie cell apertui-es, and the strong sinuous 

 8triations. (X 18.) 



Hamilton group. South of AiUnbrn, on the slmre of Cayuga lake, N. Y. 



8T1CTOPOKA TUMIILOSA. 



Pago 246. 



Fig. 18. An enlarf;t>ment. showing slightly pustuliform cell apertures, separated by longitudinal stria- 



tions. (X 18.) 

 Fig. 19. An enlargement fi-om another portion of the same frond, showing decidedly pustuliform cell aper- 

 tui-es, iri-egularly dis|>osed. (X 18.) 



Hamilton group. Vicinity of Oeneseo, Livingstun county, N. Y. 

 Fig. 20. An enlargement, .showing the obtuse distal extremity of a specimen, and the disposition of the 



cell ai)ertures in longitudinal parallel rows, separated by striations. (X ti.) 

 Fig. 21. A still further enlargement, showing moi-e distinctly the pustuliform cell apertures. (X 18.) 

 Fig. 22. An enlargement from another specimen, showing a finely granulose surface. (X 18.) 

 Hamilton group. Moscxrw, Livingston county, N. Y. 



Stiotopora a.vgulabis. 



Pago 242. 

 Fig. 23. An enlargement, showing both the oval and circular pustulose cell apertures, separated by longi- 

 tudinal ridges. 



Hamilton group. Four miles south of Le liny, N. Y. 



StICTOPOKA .SCITULA, II. sp. 



Fig. 24. An enlargement, showing the form and disposition of the cell apertures, and the longitudinal 



striations. (X 6.) 

 Fig. 2.5. A stil! fui-ther enlargement, showing more distinctly the charactera represente<l in tig. 24. (X 18.) 

 Formation and locality. Niagara group, Lockport, N. Y. 

 This fossil is one of a collection purchased fi-om the estate of the late Mr. Pickett of Rochester, N. Y., 

 an<l was originally arranged with the collections of the Hamilton group, the specimen diflering in no 

 appreciable character from the Hamilton shale. It was only after it had been drawn an(i lithographed, 

 that, finding no other specimen of the species in the extensive collections of the Hamilton group, critical 

 attention was directed to it, when a small fragment of Spirifera Niagarensis was found in the shale, and 

 from the presence of this fossil the Geological age has been determined. 



Stiotopora trilineata. 



Page 24.). 

 Fig. 26. An enlargement from near the base of the frond, showing the striations extending over the entire 



sui-fate. (X 6.) 

 Fig. 27. An enlargement, showing the circular cell apertui-es, with equally elevated, smooth peristomes, 

 and disposed in longitudinal parallel rows separated by striations. (X 18.) 

 Hamilton group. Moscow, Livingston county, N. Y. 



