Report of the State Geologist. 73 



oval, slightly oblique cell apertures, which never have the 

 pustuliforn: appearance characteristic of that species; from 

 >S'. interstriata it may be distinguished by the more broadly oval, 

 slightly oblique cell apertures, the strong sinuous striations, and 

 the absence of spinulose projections from the interior of the 

 cell aperture ; from the other species at present known in the 

 Hamilton and Upper Helderberg groups it may be distinguished 

 by the narrow, somewhat rigid form, and strong, sinuous, inter- 

 rupted ridges between the apertures. 



Formation and locality. — Hamilton group, south of Auburn, 

 shore of Cayuga lake, N. T. 



Stictopora OYata. 



Stictopora ovata. Hall. Palaeontology of New York, vol. vi, p. 248, pi. Ixiii, 



fig. 24, 1887. 



This species most closely resembles S. incrassata, but may be 

 distinguished as follows : The cell apertures are more broadly 

 oval, the larger end of the ovate aperture is toward the base, 

 the peristome is unequally elevated, the posterior portion being 

 the most prominent and oblique, the cell apertures are more 

 distant longitudinally and more closely disposed transversely, and 

 are smaller and more broadly ovate than those of that species ; 

 from the other species, at present known, from the Lower and 

 Upper Helderberg and Hamilton groups, it may be distinguished 

 by the large size and great thickness of the frond, the large ovate 

 cell apertures and the sinuous angular striation between the 

 ranges of apertures. 



Formation and locality. — Hamilton group, near the foot of Can- 

 andaigua lake, N. T. 



Stictopora incrassata. 



stictopora incrassata. Hall. Trans. Albany Institute, vol. x, p. 190, 1881. 

 *' " *' Report of State Geologist, for 1883, p. 47, 1884. 



" " " Palasohtology of New York, vol. vi, p. 249, pi. 



Ixii, figs. 1-6, 1887. 



This species occurs in association with Semiopora bistigmata, and 

 in its manner of growth closely resembles that species, but may 

 easily be distinguished by its more robust form and the absence 



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