DESCRIPTIO:^ OF SPECIES. PP. 41 



ous ; lateral nerves, passing off at an acute angle into the 

 segments or lacinise, pinnately divided, or forking ; fructi- 

 lication, j)laced on the terminal lobe of the pinnules, at the 

 extremity of the median nerve, and consisting of six sori. 

 grouped radially around a central axis.) 



The primary, and the secondary rachis, are both beauti- 

 fully channeled on the upper side, and this is a feature so 

 constant, that we may recognize fragments by its means 

 with certainty. After the figures of the plant given on 

 Plates III and IV had been engraved, fertile pinnse were 

 found, showing the character of the fructification much 

 more cleai'ly, than that given on PI. III. We are fortu- 

 nate in possessing a large number of specimens of this 

 plant, as its complex character, and the great changes that 

 it exhibits in passing from the lower to the upper part of 

 the frond, would lead otherwise to the foundation of sev- 

 eral si)ecies upon the different parts of this single plant. 

 Indeed it is difficult to do justice to it, either in a short de- 

 scription, or without using many hgures. 



The star shaped arrangement of the sori, seems to ally 

 the plant with Asterocarpiis, of Weiss, and the general fa- 

 des and nervation, with Sphe/iopteris denticidala, Brongt, 

 from the Oolite Formation. The terminal position of the 

 sori causes it to resemble the Hymenophylloid section of 

 the Sphenopterids, and in this point, it reminds us of 

 Schenk's Acropteris ciineata, from the Rliaetic. 



Habitat — Found only in the Roof shales of the Waynes- 

 burg Coal, at one coal mine, at Cassville, W. Va. 



SpTienopterls cortacea, Sp. nov., PI. V, Figs, o and 6. 



(Frond, bipinnate ; pinnae, inserted at an acute angle on 

 the broad, leathery, winged primary rachis, and terminating 

 at the summit in a three-lobed leaflet ; pinnules triangu- 

 lar in outliiie, somewhat contracted at base, and decurrent 

 on the winged secondary rachis, cut into 3 or 4 rounded 

 lobes, the uppermost one being somewhat elongated ; lateral 

 nerves obscure, or wholly concealed in the thick leathery- 

 like parenchyma of the lobes.) 



This very peculiar plant has, as yet, been found only in 



