OLDKK P0T0:MAC OF VIRGINIA AND MARYLAND. 487 



KdSSII. I'l.A.MS KKOM TIIK ( Ol.niKSTKU ItllVI). 



On Auffii.st 5, 1893, Professor Ward ohtaitiod tVoni tli(> ( olchoster 

 road in Virginia risjlit fi'agmcnts of slialc with traces of fossil [)laiits. 

 Thcv are imprints of small portions of the ultimate pinn;e of a fern 

 that resembles Tlnjrsoplcn's pachip-dclii.'^ font.," a ()Iant previously 

 (lescril)ed from Vii'oinia. Thei'e is not enough material sufficiently well 

 preserved 1o positively detennine the species. Tliis is a species charac- 

 teristic of the lower poi'tion of the Lower Potomac, the part eml;)raced 

 in Professor Wai'd's two sulxlivisions, the .lames Piver series and the 

 Rappaliannock series. The exact locality from whicli these specimens 

 were obtained is the right liank of Pohick Creek, on the west side of 

 the Cok'hester road. This is a locahty which at the time of the prepa- 

 ration of Monograph XV was not known to yiekl fossil plants. 



FOSSIL PLANTS HiOM WIIITK IIOISK HLIFF A>D JKMNT TEK\0\ iKIiOOKK HKDS). 



In the banks of the Potomac River called White House Bluff, and 

 up the river to near the Moimt Vernon Mansion, there are two different 

 horizons containing fossil plants. The lower one is that of the Mount 

 Vernon series of strata, on which Professor Ward found Mount Vernon 

 plants at two localities. These will be noticed farther on (see p. 490). 

 The upper one Ijelongs to the Ac}uia Creek series or Brooke beds, 

 and will be treated first because first discovered by me (see Monograph 

 XV, pp. 22-23). Later Professor Ward discovered a locality of this 

 age above the mouth of Doag Creek on the Mount Vernon estate. 

 It will be convenient to treat both these localities under one head. Mr. 

 WTlliam Hunter discovered in W'hite House Bluff, near my original 

 locality, a new locality for Aquia Creek plants. This is at the lower 

 or south end of the large exposure next below the original locality and 

 at nearly the same elevation above the water. These three localities 

 for Aquia Creek plants may for distinction in this paper be called "Fon- 

 taine's locality," "Hunter's known locality," and "Ward's locality." 



Li 1895 Mr. Hunter collected a few specimens in this bluff from 

 another locality, whose position was not given. These plants show 



aMonograpli XV, pp. 132, 133, pi. xlvi, figs. 3, 5; pi. xlvii, figs. 1, 2; pi. xlLx, fig. 1. 



