11 



comes gradually attenuate, until near the apex it is 

 scarcely perceptible. 



Notwithstanding the absence of a foliolate leaf under 

 the genus Neuropteris, as hitherto understood, we are 

 led, disregarding the anomaly, to refer our specimen to 

 it. Arguing from several striking coincidences between 

 the two, this course seems to be far more expedient 

 than to advance a ncAV generic name, until we are con- 

 fident that necessity demands such. 



The developement of the base, -- its cordate form 

 and its sessile adherence ; the venation ; the midrib and 

 the texture of the leaf — are all marked features of this 

 fossil impression, — perfectly agreeing Avith eminent 

 characteristics of Neuropteris. 



We assume the honour of giving, as a specific name, 

 to this singular fossil plant that of the two distinguished 

 brothers, — Professors W. B. and H. D. Rogers, — 

 which is so permanently and illustriously connected with 

 American and cosmographic geology. 



Locality, in coal formation, — Pennsylvania. 



PECOPTERIDEAE. 



ALETHOPTERIS SAUVEURII , GO PP. 

 PI. I, fig. 3. 



6opp. Syst. Jil. foss. p. 311. 

 linger, Gen. et Spec. j). 151. 



PECOPTERIS M':RV()SA, 

 King, — Edinburgh New Philos. Jour. vol. 36, p. 286, pi. o, Jig. 9. 



PECOPTERIS NERVOSA, 

 JBrong, Hist, veget. foss. I, p. 297, pi. 95, Jigs. 1, 2. 



PECOPTERIS SAUVELII, 

 Brong. Hist, veget. foss. I , p. 299, pi. 95, Jig. 5. 



