176 PALEONTOLOGY OF NEW YORK. 



Trematopora (Trematella) nodosa, n. sp. 



HOT FIGDRBD. 



ZoARiuM ramose, solid; bifurcations infrequent; branches diverging at an angle 

 of forty-five degrees, diameter 2 mm. Cells tubular, arising from the center 

 of the branch, in contact for nearly their entire length, gradually diverging 

 until near the surface, when they abruptly turn outward ; septa moderately 

 frequent. Cell apertures oval, length .30 mm., width a little more than one- 

 half the length, closely and irregularly disposed, separated by about one-third 

 the width of an aperture. Peristomes obsolete, the apertures appearing 

 immersed. Inter-apcrtural space elevated, convex, with numerous, prominent, 

 slightly oblique, conical nodes. 



The irregularly reticulated appearance of the surface, oval cell apertures and 

 numerous, prominent, slightly oblique nodes, will be sufficient to distinguish 

 this species from any other at present known in this geological horizon. 



Formation and locality. Hamilton group, Jaycox's run, between Geneseo and 

 Avon, N. Y. 



ORTHOPORA, s. g. 



(See pages 16 and 70.) 



Trematopora (Orthopora) polygona. 



NOT FIQDBBD. 



Trematopora polygona. Hall. Trans. Albany Institute, vol. x, p. 180. 1881. 



Report of State Geologist for 1883, p. 9. 1884. 



ZoARiUM ramose ; bifurcations infrequent ; branches widely diverging, diameter 

 from 1.25 to 1.50 mm. Cells tubular, arising from the center of the branch, 

 in contact for the greater portion of their length, somewhat abruptly curving, 

 and slightly separating near the surface ; walls thin, a little undulating ; 

 septa very thin and infrequent. Cell apertures oval, length .25 mm., width 

 usually about one-half the length, but sometimes not more than one-third, 

 disposed in longitudinal rows, alternating and forming oblique transverse 

 rows at an angle of forty-five degrees to the axis of the branch, the latter 

 arrangement being the most conspicuous. Surface between the apertures ele- 



