DESCRIPTION OF THE SPECIES. 77 



with much hesitation that I separate them, lleer thinks that this plant is 

 Dunker's Neiirojiteris Albertsii, but it seems to be quite different from the 

 forms figured by either Dunker or Schenk. 



Cladoimii.kuis distans, sp. nov. 



riato XIII, Figs. 4, 5. 



Frond 1)ipinnate or tripinnate; i)rincipal rachis stout and rigid; piinue 

 alternate, linear elongate, with rigid strong rachises ; pinnules oblong or 

 ovate, very obtuse, distant; leaf-substance thick and leathery, slightly fal- 

 cate, alternate, attached by the entire base ; midnerve pecopteris-like ; lat- 

 eral nerves once forked and strong-. 



Locality : Not very rare in the banks of Dutch Gap Canal ; rai-e at 

 fishing hut above the canal. 



This small fern seems to be quite restricted in its distribution. It is 

 well characterized by its pinnules, which are small in size, of leathery 

 texture, and remotely placed. 



Cladoi'hlebis, sp. ? sp. nov. 



Phite XV, Kig.U; Plate XIX, I'ig.:!. 



Frond and pinna; unknown ; [)iunules suljopposite, ovate to ovate- 

 oblong, obtuse, united at the widened base, going off nearly at a right 

 angle; midnerve as in the genus; lateral nerves once forked, or with one 

 branch of the basal i)air forking again. 



Localities : Hill-side near Potomac Run ; bank near Brooke ; very 

 rare at both places. 



This plant is too rare and found in fragments too small to permit its 

 character to be made out. It seems, however, to be quite distinct from 

 any other fern described coming from the Potomac formation. 



Cladopulebis alata, sp. nov. 



Plate XIX, Fig. 5. 



Frond tripinnatifid, arborescent ; priucipal rachis stout and rigid ; 

 pinna; alternate, curving upwards, with strong rigid rachises; pinnules 

 with thick leaf-substance, opposite or subopposite, in shape linear-lance- 



