502 Systematic Paleontology 



permit the establishment of its full character. It may provisionally be 

 regarded as a variety of Rogersia angustifolia, which it resembles in all 

 determinable points except size." — Fontaine^, 1906. 



It seems very probable that this supposed variety of Rogersia angus- 

 tifolia is based upon detached leaves of CepJialotaxopsis, but as the writer 

 has not been able to entirely satisfy himself on this point the variety 

 is retained for the present. 



Occurrence. — Arundel Formation. Langdon, District, of Columbia. 



Collection. — U. S. National Museum. 



Genus FICOPHYLLUM Fontaine 

 [Mon. U. S. Geol. Survey, vol. xv, 1890, p. 290] 



This genus was founded by Fontaine in 1890 for certain netted-veined 

 leaves which are present in considerable abundance in the Patuxent 

 formation at Fredericksburg and less commonly at a few other synchro- 

 nous outcrops in Virginia. The s|3ecimens are all fragmentary and the 

 preservation is poor so that it is difficult to arrive . at any definite con- 

 clusions regarding their true nature. 



For the sake of completeness the original discussion is quoted in full : 



" Leaves elliptical in outline, subacute, gradually narrowed at base, 

 with the lamina of the leaf more or less decurrent _ along the petiole; 

 midnerve and petiole extremely thick proportionally; lateral or primary 

 nerves proportionally and in most of the forms absolutely slender, 

 extremely irregular in arrangement, forming a lax reticulation of very 

 archaic type. Ultimate reticulation strongly marked and fern-like. 



" This genus is an important one in the Potomac flora, and has con- 

 tributed a considerable number of individuals to the vegetation of that 

 epoch. It is largely developed in association with Jurassic types of 

 plants, as at Fredericksburg, where it is most abundant, and is almost 

 wanting in the strata where more modern elements abound, as at Brooke, 

 White House, and Baltimore. As illustrating the archaic and peculiar 

 features of these leaves and those of Protecephyllum, I may state that 

 for some time no other leaves but these were found at Fredericksburg, 

 and finding them associated only with plants of Jurassic facies T found 



