504 ilESOZOIC FLORAS OF UNITED STATES. 



KOSMI, I'l.A.MS HtdM IIKI.I, 11(11, K. 



[PI. LXXX. No. 147.] 



On April 7. 1S9G, Mr. Arthur Bibhins collected for the :\Iar\]aiHl 

 Survey a considerable ninnl)er of fossil plants from a locality called 

 Hell Hole, on the Virginia side of the Potomac River. This locality 

 is between Mount Vernon and White House BlufT, l)ut some distance 

 above Professor Ward's locality. Most of the rock matter is grayish 

 chocolate-colored, arenaceous clay, which preserves the plants fairh' 

 well. Some is a chocolate clay. The following is the list of fossils 

 obtained here: 



Aristolochifephylliuii crassiiiorve Font 2 spociinens. 



Atlu'otaxopsis expaiisa Font 2 specimens. 



Baieropsis foliosa Font 9 specimens. 



Baieropsis longifolia Font 1 sjiecimen. 



Baieropsis pluripartita Font ,3 specimens. 



Carpolithus virginiensis Font 1 specimen. 



Celastrophyllum brookense Font. I 2 specimens. 



Cladophlebis constricta Font. ? 2 specimens. 



Ficophyllum tenuinerve Font. ? 6 specimens. 



Frenelopsis ramosissima Font. ?.. 1 specimen. 



Leptostrobus longifolius Font. 1 specimen. 



Menispermites virginiensis Font. ? 3 specimens. 



Onychiopsis psilotoides (Stokes & Webb) Ward 3 specimens. 



Sassafras bilobatiim Font. ? 1 specimen. 



Sequoia ? inferna Ward nom. nov 2 specimens. 



Sphenolepidium Stcrnbergianum densifoiium Font 19 specimens. 



ThjTSopteris divaricata Font. ? 1 specimen. 



Baieropsis foliosa Fontaine. 

 Pi. ex, Fig. 9. 



1889. Baiero2)sis foliosa Font.: Potomac Flora (Monogr. U. S. Geo!. Surv., Vol. XV), 

 p. 209, pi. xciii, figs. 4, 4a, 5, 6, 6a. 



X^ine specimens of this species occur at Hell Hole, but even the 

 best of them contain only a small portion of the plant. This is a spe- 

 cies highly characteristic of the Aquia Creek horizon in Virginia. The 

 specimens from Hell Hole show lacinia? even more slender tlian the 

 Mrginia forms. PI. CX, Fig. 9, gives one of these. It bears the num- 

 ber M. G. S., 8431. 



