DESCRIPTION OF SPECIES. PP. 71 



line, with a stout and rough rachis ; secondary i^innae long, 

 narrow and pointed, alternate, departing from the main 

 rachis under an angle of 60° ; secondary rachis, terete, 

 straight, and rather strong ; pinnules, rounded at the apex, 

 slightly falcate, alternate, all inclined forward, or obliquely 

 inserted, and decurrent ; primary nerve of the pinnules 

 slender, but distinct ; secondary, or lateral nerves, diverg- 

 ing at an acute angle, forking once near the insertion, and 

 each branch, or only one, again forking before reaching the 

 margin. 



This plant seems to stand about midway between Pecop- 

 teris and Callipteridium. for it has some of the features of 

 the latter genus in its nervation. The primary nerve how- 

 ever does not split up soon enough to form a true Callip- 

 teridium. The Pecopteris nearest allied to it is probably 

 P. pteroides^ Brongt., from which it differs in its long, 

 ■pointed pinnse, and also in the shape, insertion, and ner- 

 vation of the pinnules. It resembles some of the Rhaetic 

 Cladophlebids. 



Habitat. — Roof shales of the Waynesburg Coal, Cassville, 

 West Virginia. 



Pecopteris rarinervis. Sp. nov., PL XX, Figs. 6, 7 and 8. 



(Frond bipinnate ; primary rachis slender and smooth ; 

 pinnae alternate, linear-lanceolate, and going off at nearly 

 a right angle ; secondarj' rachis, slender and rigid ; pin- 

 nules alternate, short, ovate, rounded at the apex, united 

 for a short distance above the base in the lowest ones, and 

 becoming more united as we pass up towards the summit 

 of the frond, where the pinnae pass into pinnules of linear 

 shape, with undulate margins ; primary nerve of the pin- 

 nules distinct, and somewhat llexuous ; secondary nerves 

 few, passing off at an acute angle, and forking dichoto- 

 mously.) 



The nervation of this plant is similar to that of Pecopteris 

 Bredovi, Germar. The primary nerve is more distinct in 

 our plant, and the facies differs somewhat from that of 

 Germar' s species. 



