544 



THE DEVONIAN PERIOD. 



of doubtful nature. They must have been stems or roots, bifur- 

 cating in the manner of Psiloiyhyton, but having a very slender 

 woody axis. They may have been either roots of some plant, or 

 stems of a smooth and comparatively succulent species of Psilophyton. 



Fig. 190.— Cordaites Rohhii. 



{a) Group of young leaves. 

 (6) rointofleaf. 



(c) Base of leaf. 



{(1) Venation; magnified. 



Cordaites Rolbii, Dn. (Fig. 190). Leaves elongated, lanceolate, 

 sometimes three inches wide and a foot in length. Veins equal and 

 parallel. Base broad, clasping the stem, point acuminate. When 

 this species was described in my paper in the " Canadian Naturalist,"* 

 only very imperfect specimens were in my possession ; but numerous 

 and fine specimens recently found now enable me more pei'fectly 

 to characterize the species. Tlie leaves vary much in form ; and 



* May 1861, p. 168. 



