278' Systematic Paleontology 



discussion under Onychiopsis Gcepperti, which is retained as a distinct 

 species. 



Occurrence. — Patuxent Formation. Fredericksburg, Dutcli Gap, 

 Trents' Eeach, near Potomac Eun, Virginia; New Eeservoir, 16th Street, 

 District of Columbia. Arundel Formation. Langdon, District of Col- 

 umbia; Bay View, Maryland. Patapsco Formation. Federal Hill 

 (Baltimore), Stump ]S[eck, near Wellhams, Maryland; near Brooke, 

 Widewater, Hell Hole, Virginia. 



Collection. — U. S. National Museum. 



Onychiopsis brevifolia (Fontaine) Berry 

 Plate XXXIV, Figs. 1, 2 



Thyrsopteris 'brevifolia Fontaine, 1890, Mon. U. S. ' GeoL Surv:, vol. xv, 



1889, p. 121, pi. xxlv, figs. 5, 10. 

 Thyrsopteris dentata Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 1889, 



p. 121, pi. xxiv, figs. 4, 6, 7, 9; pi. xxv, figs. 1, 2. 

 Thyrsopteris pachyphylla Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 



1889, p. 135, pL 1, fig. 3. 

 Thyrsopteris nana Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 1889, 



p. 141, pi. Ivi, figs. 4, 8. 

 Thyrsopteris heterophylla Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 



1889, p. 142, pi. Iviii, fig. 3. 

 Thyrsopteris sphenopteroides Fontaine, 1890, Mon. U. S. Geol. Surv., vol. 



XV, 1889, p. 143, pi. Iviii, fig. 6. 

 Thyrsopteris squarrosa Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 1889, 



p. 143, pi. lix, fig. 3. 

 Thyrsopteris retusa Fontaine, 1890, Mon. U. S. Geol. Surv., vol. xv, 1889, 



p. 144, pi. lix, fig. 10. 

 Thyrsopteris 'brevifolia Fontaine, 1899, in Ward, 19tli Ann. Rept. U. S. 



Geol. Surv., pt. ii, p. 660, pi. clxi, figs. 10-15. 

 Onychiopsis brevifolia Berry, 1911, Proc. U. S. Natl. Mus., vol. xli, p. 329. 



Description. — Frond small, bipinnate or tripinnate. Eachises rather 

 slender, often winged. Pinnas alternate to subopposite, relatively long 

 and narrow, divided below, pinnatifid distad. Pinnules much narrowed 

 at the base, decurrent, obliquely toothed or divided, the extent depending 

 upon their position on the frond, triangular ovate to lanceolate in out- 

 line. Veins somewhat tlabellate, once or twice forked or simple. Tex- 

 ture coriaceous. 



This species is not common in the Potomac and is confined to the 

 basal beds in the Virginia area, although it has also been reported from 



