Maryland Geological Survey 497 



asarifoUa Zigno and Protorhipis reniformis Heer which do not appear to 

 be related to the Cretaceous forms just mentioned nor to the true 'Proto- 

 rhipis but apparently represent detached scales of some Zamiostrobus 

 or similar object as has been suggested by Kathorst and others. 



This long discussion terminates at about the point where it started 

 except that it appears clear that Protecephyllum is not a fern of the 

 Protorhipis type. An additional species recently described by Fontaine 

 from the Californian Shasta does not help any since the latter is 

 absolutely undeterminable and uncharacteristic* 



There are a number of somewhat similar foliar, stipular, or bracteate 

 objects described by Saporta from the Cretaceous (Albian) of Portugal 

 with which the reniform Potomac species may be compared, such as 

 Braseniopsis venulosa^ B. villarsioictes^ and Adoxa proetavia,^ but these 

 comparisons are worth little. The only possible view of their botanical 

 relationship is that they are either angiospernLOus or filicinean. They 

 may represent aquatic forms of either type or juvenile forms of the fronds 

 of some dimorphic Lower Cretaceous fern. With regard to the ovate 

 forms of ProtecBphyllum with a midrib these may also be angiospermous 

 or they may be related to Ficophyllum. and Rogersia, which may be 

 early representatives of the Gnetales. They suggest, rather remotely 

 it is true, the two specimens from the Stonesfield slates of England 

 which are described and figured by Seward as simply Phyllites sp.* 

 Probably it would have been better in the first instance to have described 

 these Potomac forms as Phyllites instead of making them the basis of 

 six different species of angiosperms, but as they are in the literature and 

 the name does not carry any implications of relationship, it has seemed 

 best to retain it, reducing, however, the six nominal species to the two 

 which are actually present in nature. Their true affinity remains 



^Font, in Ward, Mon. U. S. Geol. Survey, vol. xlviii, 1906, p. 267, pi. Ixix, 

 fig. 11. 



^ Saporta, Fl. Foss. Portugal, 1894, p. 192, pi. xxxiv, figs. 1-4. 



^ IMd., p. 195, pi. XXXV, fig. 9. 



* Ibid., p. 187, pi. xxxiv, fig. 5. 



' Seward, Jurassic FL, pt. ii, 1904, p. 152, pi. xi, figs. 5, 6. 



