DESCKTPTIOX OF SPECIES. PP. 77 



This plant resembles P. arborescens somewhat; but the 

 union of the pinnules, the nervation, and the insertion of the 

 pinnules distinguish it from that species. It was evidently 

 a very fleshy plant, as the nerves are usually so deeply 

 buried that they are seen with difficulty. 



Habitat. — Roof shales of the Waynesburg Coal, West 

 Union, West Virginia. 



Pecopteris Heeriana, Sp. nov., PL XX Y, Figs. 3-7. 



(Frond, tripinnate; secondary pinnse, alternate, somewhat 

 flexuous, going oif at nearly a right angle ; pinnules, 

 slightly falcate, remotely placed and decurrent on the 

 rachis, so as to render it distinctly winged ; lowest pinnule 

 on the lowest side, often inserted partly on the principal 

 rachis ; pinnules on the lower portion of the plant, notched 

 or lobed ; mid-nerve, well defined and extending to the apex 

 of the pinnule ; lateral nerves, going off at an acute angle, 

 forming 4 or 6 pairs, simple ; fructification, composed of 

 numerous shield-shaped sori covering the surface of the 

 pinnule.) 



The texture of the pinnules is thick and leather-like, usu- 

 ally obscuring the nerves. The plant presents a type un- 

 usual in the Carboniferous strata, but characteristic of the 

 Rhaetic flora. It belongs to Schimper's section of Pecop- 

 teris acrostichides, and recalls forcibly the appearance of 

 Pecopteris Williamsoni,Brongt., both in the form of the pin- 

 nules, and in the character of the fructification. Named in 

 honor of Dr. Oswald Heer of Zurich. 



Habitat. — Roof-shales of the Waynesburg Coal, Cass- 

 ville, W. Va. 



Pecopteris tenuinervis. Sp. nov., PL XXYIII, Figs. 1-4. 



(Frond, tripinnate; primary rachis, strong, and somewhat 

 rigid ; secondary pinnae, linear-lanceolate, alternate, closely 

 placed, becoming gradually shorter towards the apex of the 

 primary pinna, thus giving this a triangular outline ; pin- 

 nules very short, narrow and alternate, the lowest one, on 

 the lower side, always heteromorphous. it having a crenu- 

 late margin, and being larger than the rest ; pinnules to- 



