OLDEIJ POTOMAC OF VIRGINIA AND MARYLAND. 481 



C'lvok." The locality is not iiioiv precisely si;iven, hut it is probably that 

 (lesciihed in Monoffi'aph XV as "72cl IMilepost." The following j)lants 



occui- in that collection: 



* 



Baicnjpsi.s ])iurip;u-tita l'"(iiit 16 specinions. 



Sapiiulopsis brevil'ulia I''()iit 5 specimens. 



Sapindopsi.s magnifolin Font _. _ 1 specimen. 



Supiiulopsis vai'iahilis Font 10 specimens. 



Xo new forms not described in Monograph XA' as found at this 

 locality occur in the collection, and hence there is no i-ea.son foi' cluuiging 

 the conclusion drawn in that work foi' the age of the formation. The 

 age was determined as A(|uia Creek. 



KOSSIl, I'l.AMS KKIIM .\KA1! TIIK TJII IIII.KI'OST. 



On May 4, 1892, Professor Ward discovered a new plant locality, a 

 short distance north of that of the 72d Milepost, at the end of the railroad 

 cutting and below the tracks, on the west side. On July 28, 1893, I 

 visited the place in company with Professor Ward and we made a col- 

 lection larger than that made by him. The clay containing the plants 

 shows its top in a drain below the level of the roadbed. It forms an 

 undisturbed lens in the partially inchirated sands. This clay no doubt 

 represents a lens similar to that which was torn up to form the redepos- 

 ited clay particles at the 72d Milepost. Xo plants were found here which 

 had not previously been found in the same general region. The following 

 is the list of species found here: 



Aristolochiaephylliim crassinerve Font 8 specimens. 



Baieropsis foliosa Font 3 specimens. 



Glyptostrobus (Taxodium) brookensis (Font. ) Ward 1 specimen. 



Leptostrobus longifolius Font 1 specimen. 



Suj)in(loj)sis magnifolia Font 1 specimen. 



Sphenolepidium Sternbergianum densifolium Font 1 si)e<-imen. 



Sphenolepidium virginicum Font 1 specimen. 



Akistolochi^phyllum crassinerve Fontaine. 



Pi. CIX, Fig. 1. 



1889. AristolocMiephijUum crassinerve Font.: Potomac Flora (Monogr. U. S. Geo). 

 Surv., Vol. XV), p. :V22, pi. clx. figs. 3, ;3a, 4-6. 



The large coai'se leaves of AriMolochi(('})hyIlum crassinerve. occur in 

 a considerable number of fragments. Some of them are larger and better 



MON XLVIII — 05 31 



