286 THE POTOMAC OE YOUNGER MESOZOIC FLOEA. 



proximately parallel to the margin for some distance, not meeting one 

 another; the primary nerves sending off branches in a dichotomous manner, 

 and these anastomosing to form large, irregular, lax primary meshes ; the 

 ultimate meshes, elongate and mostly quadrangular, rather indistincth^ de- 

 fined, owing to the thick leaf-substance. 



Locality : Fredericksburg ; rare. 



The nervation of this plant is more like that of Pyotdephijllum uimfnm 

 than any other in the size and loose texture of the midnerve, the slender 

 primary nerves, and the irregular lax nervation ; it is proteaceous, but com- 

 bines with the characters of the Protcacece some of those of the Celasfrinece. 

 Indeed, we may say generally of the leaves of I'rofccqihifUmu with a mid- 

 rib, that they combine features of the nervation of both these genera. This 

 species may be compared with Persoonia daphnoides. It belongs to the elon- 

 gate section of Protecephjllum. Fig. 2 is a restoration from several specimens. 



Prote^ephyllum tenuinekve, sp. nov. 



Plate CL, Fig. 13 ; Plate CLVI, Fig. 2. 



Shape of leaf unknown ; leaves apparently of large size and elongate . 

 leaf-substance thick; midnerve extremely thick, loose-textured, and appar- 

 ently somewhat succulent ; primaiy nerves extremely slender, going oft" at 

 a more or less acute angle, then arching backwards and splitting up into 

 branches that are nearly as strong as the primary nerves. These branches 

 meet obliquely to form oblong or elliptical irregular primary meshes of 

 large size ; ultimate nervation not visible. 



Localities : Fishing hut above Dutch Gap Canal ; road-side near Poto- 

 mac Run ; rare. 



These leaves are remarkable for the striking contrast in the size of the 

 midnerve and the primary nerves. They really possess no distinct primary 

 nerves. The nervation is a good deal like that of some Pcrsoonius. The 

 leaf must have been very large. 



PrOTE^PHYLLUM DENTATtJM, sp. UOV. 

 Plate CLVI, Fig. 7 ; Plate CLXXII, Figs. 1, 4 ; Plato CLXXIII, Figs. 12, 14. 



Leaves small, orbicular in outline ; leaf substance thin, margins cut into 

 acute or subacute ovate teeth, which are directed forwards, and are of vary- 



