DESCRIPTION OF THE SPECIES. 93 



imens have been found at these h)caHties. It is proljable that Meek's spec- 

 imens come from a hij^her k'vel, as the hori/Ani of the Belt and (\>vin<>ton 

 streets phints is not often exposed, and is sliown only in excavations made 

 near the level of these streets. 



Sphenoptekis spatulata, sp. nov. 



Plate L, Fig. 1. 



Frond nnknown ; pinna" small, short, alternate, terminated with a 

 denticulate segment like the ujjpermost lohes or pinnules ; pinnules 

 minute, lower ones spatulate and triple-toothed, upper ones spatulate and 

 obscurely toothed ; leaf-substance thick and leather^-, nerves not seen. 



Locality : Entrance to Trent's Reach ; very rare. 



The plant is so rare and fragmentary, that its full character can not be 

 made out. It seems to be a new species, characterized by its thick leaf- 

 substance and very minute size. 



Sphenoptekis pachyphylla, sp. nov. 



Plate L, Pig. 5. 



Frond uidviiown ; rachis of the penultimate pinnae very thick in pro- 

 portion to the other dimensions, apparently succulent; ultimate pinn;e or 

 pinnules very short ; pinnules or lobes broadly elliptical in outline, cut 

 obliquely into oblong miiuitely dentate lobes ; leaf-substance thick and 

 leathery ; nerves not seen. 



Locality: Entrance to Trent's Reach; very rare. 



Although this plant is very rare and fragmentar}^ it differs from all 

 others known to me in the very thick main rachis and the very small seg- 

 ments into which the [jiunules are cut. 



ASPIDIUM, Swartz. 



The genus Aspidium seems to be largely represented in the Potomac 

 flora. The number of species is considerable, and the large number of 

 individuals belonging to each species seems to indicate that ferns of this 

 group were among the most common ones. The plants are quite commonly 

 fructified, the fructification being often very well preserved. The large 



