FOSSIL FLORA. 65 



PLATE XXIV. 



" Crested Aspidiaeia." 



{Aspidiaria cristata, of Presl. 

 Sigillaria appendiculata, Brongniart. 

 Aphyllum cristatum, Artis.) 



The fossil here represented is part of the stem of a tree nearly forty feet long, and two feet 

 in diameter, found imbedded in sandstone at Banktop, Yorkshire. 



The cicatrices of the petioles are obovate, and have a central oblong crest or ridge ; the 

 interstices form deep angular furrows. 



The stems with this type of sculj^turing, are supposed to belong to a group of extinct 

 vegetables, which held an intermediate place between the Sigillaria, previously described, and 

 the Lepidodendra ; together with the latter, and certain true Coniferas and arborescent ferns, 

 these trees appear to have constituted the principal forests of the Carboniferous epoch. 



