316 THE POTOMAC OR YOUNGER MESOZOIC 1<^L0RA. 



MYRIC.EPHYLLUM DENTATUM, sp. IIOV. 

 Plate CLYI, Fig, G. 



Leaves small, linear-oblong, base and summit not seen ; margins cut 

 deeply into acute teeth that are turned forwards and often double ; leaf- 

 substance thick, leaves quite narrow ; midnerve strong ; primary nervation 

 not seen. 



Locality : 72d mile-post, near Brooke ; very rare. 



PLATANOPHYLLUM, gen. nov. 



In this genus I place leaves that in general resemble Flafanus, but 

 which can not be certainly placed in that genus. The generic description, 

 as there is only one species, is essentially the same as that of the species. 



Platanophyllum crassinerve, sp. nov. 



Plate C'LVm, Fig. 5. 



Shape of leaf not seen, leaf apparently quite large ; margins not pre- 

 served on any specimen ; midnerve very strong, especially toward the 

 base ; basal pair of primaries much stronger than those higher, sending off 

 on the lower side near the base a strong nerve ; the primaries are arched 

 strongly upwards and send off branches mainly on the lower side ; branches 

 going off nearly at right angles connect the primaries, and by forking 

 freely and anastomosing they form subrhombic elongate meshes that stand 

 with their longer dimensions nearly at right angles with the primaries. 



Locality : Deep Bottom ; very rare. 



This plant, in the strong lower basal branches sent off from the lower 

 primaries, resembles Aralmphyllum, but they are not so strong as in this 

 genus. It also vQ?,Qm\i\Gii Hcdera platanoides Lesq. 



ARALIJ^PHYLLUM, gen. nov. 



Leaves more or less fan-shaped, divided more or less deeply into three 

 principal lobes, the middle or terminal one subrhombic or elliptical in out- 

 line, rapidly narrowed to an acute tip, and separated from the lateral lobes 

 by broad sinuses rounded at the bottom; the lateral lobes divided into two 



