GEOLOGICAL SOCIETY OF PENNSYLVANIA. 323 



much of the previous difficulty. Some of the Iritter 

 specimens are distinctly lobated at their extremities, and 

 obscurely so at their sides. On re-examining our figure 3, 

 traces of the same character were faintly discerned on 

 the older leaves, and thus one of the sources of embarrass- 

 ment in naming this plant is removed. We refer to the 

 work of M. A. Brongniart, pi. 45, for some of the char- 

 acters which are partially traced in our sketch. 



Fig. 6. 



This fragment is probably a Sphenopteris of another 

 species, whose leaves are more strongly lobated and more 

 deeply impressed upon the stone. 



Pecopteris? Fig. 4. 



Something approaching to this figure occurs in pi. 97 

 of Brongniart. The arrangement of the nervures is here 

 distinctly exhibited ; its organization is most distinctly 

 yet delicately defined : and the drawing accurately rep- 

 resents these characters. 



Fig. 5. 



W e are unable to decide with precision upon this 

 plant, of which several examples are found in our col- 

 lection. Its structure and the arrangement of its leaves 

 are obscurely developed in so minute a specimen. There 

 appear some reasons for referring it, although doubtfully, 

 to the genus Thuytes of Sternberg. 



On looking over this imperfect list of plants, it will be 

 seen that they all are cryptogamous, Cellulares, or Aco- 

 tyledones, with the exception of Thuytes, and they be- 

 long to genera whose species are distributed abundantly 

 amongst the coal vegetation of all parts of the world ; but 

 the present species are new to us. The most recent, 

 but at the same time the most doubtful, genus, is that of 

 Thuytes, a dicotyledonous plant. The four species 



