DESCRIPTION OF SPECIES. PP. 61 



brandies ; lateral nerves, near the base twice-forked, in as- 

 cending only once forked, with one of the branches again 

 forlving, uppermost nerve only once forked.) 



This plant is peculiar in many respects. The nerves, and 

 facies of the pinnules, resemble the genus Cladoplilebum 

 established by Schimper for certain perculiar Pecopterid 

 forms which characterize the Rhsetic and Oolite formations. 

 Its heteromorphous pinnules ally it to Odontopteris. It is 

 much like the plant described by Weiss in his Foss. Flor. 

 d. Stein, und Rothl. under the name of Neurojpterls cor- 

 dato-ovata^ PL I, Fig. 1. 



Our plant evidently belongs to the same type as Weiss' . 

 Neither of them are truly neuropterid, and indeed there is 

 no genus which will properly include this composite type. 

 It would seem best to form a new genus to receive them, 

 which could thus include all plants with the pinnules of 

 Pecopterid type, combined with heteromorphism in the 

 lower ones, and containing the nervation of Neuropteris. 

 This might be styled " Pecopteridium.^^ The generic char- 

 acter would then be : Frond bi or tripinnate ; pinnules uni- 

 ted at base, the lower pinnules on each pinnae constricted 

 near the base, the rest ovate and attached by a broad base ; 

 midnerve quickly dissolved into branches ; lateral lower 

 nerves twice forked, upper nerves once forked. 



We place it however provisionally in the genus Callip- 

 teridium. 



Pecopteris, Brongt. 



This genus, in the Upper Carboniferous Flora of West 

 Virginia, is richer than any other in the number of species, 

 and, with the exception of Neuropteris, in the number of 

 individuals also. The section Cyatheides furnishes the 

 greatest number of species and individuals. While some 

 species occurring at lower horizons are found here, yet the 

 facies, as a whole, is changed by the addition of many new 

 forms, and we find ourselves compelled to add considerably 

 to the already long list of Pecopterids. 



