Maryland Geological Survey 263 



oblong-lanceolate, terminating in an elliptical obtuse pinnule or lobe, 

 which is similar to the pinnules lower down on the pinna; lower pin- 

 nules distant, elliptical in shape, obtuse, attached by the middle of the 

 much narrowed base, or by the midnerve alone ; upper pinnules attached 

 by the entire widened base ; uppermost ones united towards the tip of 

 the pinnae; all very thick and leathery in texture; lateral nerves not dis- 

 tinct, 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." — Fontaine, 1890. 



No new material is available for study and the type material is very 

 poor. While it is probable that this does not represent a distinct species 

 no definite conclusion is possible without more abundant and better pre- 

 served material. 



Occurrence. — Patuxent Formation. Near Potomac Run, Virginia. 

 Patapsco Formation. Near Brooke, Virginia. 



Collection. — U. S. National Museum. 



Dryopterites dentata (Fontaine) 



Aspidium dentatum Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 1889, 



p. 102, pi. XXV, figs. 6, 7, 14, 15. 

 Aspidium microcarpum Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 



1889, p. 103, pi. lix, figs. 2, 12; pi. Ix, figs. 6, 7. 

 Dryopteris dentata Knowlton, 1898, Bull. U. S. Geol. Survey, No. 152, p. 91. 

 Dryopteris microcarpa Knowlton, 1898, Bull. IT. S. Geol. Survey, No. 152, 



p. 92. 



Description. — "Frond tripinuate; principal rachis comparatively 

 stout and rigid; ultimate pinna3 alternate, very short, linear-lanceolate; 

 pinnules membranaceous, alternate, lower ones separate to the base, upper 

 ones united and reduced to lobes; lower pinnules broadly ovate, acute, 

 narrowed to the base, and subpetiolate, cut nearly to the midnerve into 

 ovate, acute teeth, reduced in the upper part of the compound pinnae 

 to ovate, obtuse lobes and teeth; sori very small, subreniform or globose, 

 placed within the margin on the summit of the alternate simple lateral 

 nerves; nerves in each of the pinnules and lobes, composed of a mid- 

 nerve, with simple alternate lateral ones on each side; in the uppermost 



