DESCRIPTION or THE SPECIES. 95 



Its relative abundance at Fredericksburg may be due to the fitness of the 

 phint for preservation, since it has a leathery durable leaf-substance. To 

 judge from the specimen given in PI. XII, Fig. 1, the }dant must have 

 attained a very large size, for this specimen is probably merely a com- 

 pound pinna not of primary rank. Fig. 3 of the same plate pr(jbal)Iy 

 represents a similar part of the frond, but down lower, where the pinnules 

 show incipient toothing. Fig. 5 of this plate shows jjinnules wider than 

 usual, with slightly undulate margins. Fig. 6, same plate, probably comes 

 from the uppermost part of the frond, where the ultimate pinna- are 

 reduced to lobed pinnules. 



The ultimate pinnaf of the lower part of the frond, as shown in PI. XL, 

 Fig. 3, must have been very long. Fig. 6 of the same plate may possibly 

 belong to a dift'erent species, but more probably represents a somewhat 

 abnormal form coming from high up on the frond. PI. XIX, Fig. 7, gives 

 opposite ultimate pinna\ a rare occurrence. The sori in this fern are 

 proportionally very large. 



The plant has no close affinity with any described fossil known to me. 

 It is nearer Asjiidiiiiii Ocrskdi^ lleer, than any other. 



ASPIDIUM ELLIPTICUM, Sp. UOV. 

 Plate XIII, Figs. 9, 10. 



Frond bipmnate or tripinnate, arborescent; rachis of the principal 

 pinna stout and rigid; ultimate pinna; alternate, short, oblong-lanceolate, 

 terminating in an elliptical obtuse pinnule or lobe, which is similar to the 

 pinnules lower down on the pinna; lower pinnules distant, elliptical in 

 shape, obtuse, attached by the middle of the much narrowed base, or by 

 the midiierve ahine; upper pinnules attached by the entire widened base; 

 uppermost ones united towards the tip of the pinna-; all verv thick and 

 leathery in texture: lateral nerves not distinct, but apparently simple, and 

 bearing the sori on their summits; sori pear-shaped or truncate-elliptical, 

 in two rows, one on each side of the midnerve; sterile forms not seen. 



Localities: Hill-side near Potomac Run; bank near Brooke ; rare. 



'Compare Flor. Foss. Arc, vol. 6, part 2, Foss. Flor. Gronlands, PI. XXXIV. 



