DESCRIPTION OF THE SPECIES. 1 1 1 



leaf-substance tliick and leathery; midnerve neuropteris-like, and vanish- 

 ing before attaining the apex of the pinnules; lateral nerves occur in the 

 lower portions of tlie pinnules mostly in nerve grouj)s; all go off ver\- 

 obliquely and fork usually several times, very fine and closely placed, but 

 distinct. 



Localities: 72d mile-post, near Brooke, common, and the most abun- 

 dant fern; road-side near Potomac Run; rare. 



All the specimens figured, except that in PI. XVIII, Fig. 6, come from 

 the 72d mile-post, near Brooke. Strange to say, while the phuit is abun- 

 dant at the 72d mile- post, not a trace of it can be seen at the "bank" near by. 

 This is a striking illustration of the localization of the species in this flora. 



Taken as a whole tins Thiinifeldia is unlike any described fos.sil. 

 Some of the pinnules in shape remind one of T. rhomboidulls Ett, given 

 by Schenk.^ 



TlIINNFELUIA GRANULATA, Sp. nov. 

 ri.ato XXVI, Fig,s. 10-12; Plato XXVII, Figs. 1-5, 8; Plate CLXIX, Fig. 1. 



Frond bipinnate or tripinnate ; rachises comparatively stout; leaf- 

 substance thick; pinnules varying in size and shape with their position on 

 the piniue and frond; in shape they are ovate-elliptical to subrhombic, the 

 lower ones irregularly cut into oblong to elliptical lobes ; the lower surface 

 of the pinnules has a very fine granulation between the nerves, which can 

 be seen distinctly only by the help of a lens ; nerves closely placed, very 

 fine but distinct on the under surface of the pinnules, repeatedly brandling 

 and diverging flabellately. 



Localities : Fishing hut above Dutch Gap Canal, and road-side near 

 Potomac Run ; rare. 



The plant occurs more commonly at the former locality, where several 

 specimens were found. It is very rare at the locality near Potomac Run. 



TaiNNFKLDl.V ROTUNDILOBA, Sp. UOV. 

 riato XXVII, Figs. 6. 7. 



Frond bipinnate or tripinnate ; principal rachis rather .stout; pinnules 

 with thick texture, alternate, lu'oadly ovate in outline, obtuse, cut more or 



' Foss. Flor. tier GrenzschicUten, PI. XXVII, Figs. 4, 5. 



