UPPER HELDERBERG GROUP. 



DESCRIPTIONS OF SPECIES. 



Trematopora (Trematella) annulata. 



PLATE XXV, FIGS. 22, 23 ; and PLATE XXVI, FIGS. 1, 2. 



Trematopora annulata, Hall. Trans. Albany Institute, vol. x, abstract, p. 5. 1881. 



Report of State Geologist for 1882. Expl. pi. 24, tigs. 1, 2. 1883. 

 TremaMla '• " Report of State Geologist for 1885, advance sheets. Expl. pi. 25, figs. 22, 



23. 1886. 



ZoARiUM ramose, solid ; branches from 2 to 3 mm. in diameter ; bifurcations 

 occurring at intervals of from 4 to 15 mm. Cells tubular, arising from the 

 center of the branch and regularly curving to the surface ; in cont<act for the 

 greater portion of their length ; diverging and leaving a short intercellular 

 space as they approach the surface ; septate, septa closely disposed. Cell 

 apertures polygonal, diameter .25 mm.; irregularly disposed, lisually in contact, 

 frequently with small spinules at the angles. Pseudopores small, infrequent. 

 Monticules elongate, transverse to the branch ; two or more are usually in 

 the same line giving to the branch an annulated appearance. There is a 

 narrow space along the middle of each monticule usually destitute of cell 

 apertures, but frequently with small pits or pseudopores. 



Formation and locality. Upper Helderberg group. Falls of the Ohio river. 

 Trematopora (Trematella) arborea. 



PLATE XXV, FIGS. 16-21. 



TWmatopora arborea. Hall. Trans. Albany Institute, vol. x, abstract, p. 5. 1881. 



Trematella " " Report. of State Geologist for 18S5, advance sheets. Expl. pi. 25, figp. 10-21. 



1 886. 



ZoARiUM ramose, solid; branches from 2 to 3 mm. in diameter; bifurcations 

 occurring at intervals of from 2 to 7 mm. Cells tubular, polygonal, gradu- 



