DESCRIPTION OF THE SPECIES. • 85 



enforniation, Plate V, Fig-. 2. l^lie Potomac plant is, however, a .stronger 

 form, and the nerves are more commonly single, straight, and parallel than 

 in the Wealden fern. 



Pecoptekls Ovatodkntata, sp. nov. 



PKate XV, Fig. 8; I'l.ate XXII, I'ig. 12; Plate XXIII, I'ijj;. 1. 



Frond bij)innate or tripiiniate, arborescent; pinnules or reduced pinme 

 suboppOsite, linear acute, separate to the narrowed base, slightly decur- 

 rent, margins cut distinctly into ovate-subacute teeth; midnerve continued 

 to the summit of the pinnules or pinna;; lateral nerves furcate. 



Localities: Fredericksburg; entrance to Trent's Reach; fishing hut 

 above Dutch Gap Canal; rare at all localities. 



This plant is more common at the Dutch Gap localities than at Fred- 

 ericksburg, but is nowhere abundant. This fossil is found in fragments 

 too small, and occurs too rarely to permit its true character to be made 

 out. It is not close to any previously described fossil known to me. 



Pecopteris Microdonta, sp. nov. 



Plato XIX, Fig.8 ; Plato XX, Figs. ,^ U. 



Frond bipinnate or tripinnate, arborescent?; principal rachis strong 

 and woody; jtinna' of the ultimate order opposite, with a rigid racliis; pin- 

 nules lanceolate-acute, somewhat falcate, slightly narrowed and decurrent 

 at base, attached by the lower portion of the base; distinct, with margins 

 cut into small ovate-acute teeth; midnerve strong at base, lateral nerves 

 in each tooth simply forked, or in the lowest teeth with the upper branch 

 again forked. 



Localities: Fredericksburg; entrance to Trent's Reach; near Dutch 

 Gap Canal; at each place rare. 



The specimen from the Dutch Gap locality, PI. XX, Fig. 11, has a 

 somewhat ditforent facies from the Fredericksburg form, PI. XIX, Fig. 8, 

 the pinnules being longer and proportionally nari'ower. The specimens 

 found indicate that the plant was large and probably arborescent. 



