656 PROCEEDINGS OP THE BALTIMORE MEETING 



Fontaine and Ward have described or listed about 737 species of fossil plants 

 in 198 genera. 



Considering for a moment their areal distribution, we find a practically con- 

 tinuous belt from Alexandria to Fredericksburg. Near Fredericksburg the 

 Eocene is found capping the Cretaceous outcrops, until south of that town the 

 latter are entirely covered as far as the vicinity of Dodson, where a few 

 streams have trenched the Cretaceous beds in a limited area. From Dodson to 

 Richmond they are again buried by both Eocene and Miocene deposits. Be- 

 tween Richmond and Petersburg the James and the Appomattox rivers have 

 cut channels, along which excellent Lower Cretaceous sections are exposed 

 from these towns seaward almost to where the Appomattox enters the James at 

 City Point. Southward from Petersburg to the North Carolina line the Cre- 

 taceous is again buried, only showing itself in the stream bed of the Nottaway 

 river. 



These deposits are separable into two series, an older and a younger. The 

 older is more or less conglomeritic, with much cross-bedded arkosic sands, con- 

 taining cobbles and clay balls and lenses of green clay, the latter due to the 

 chloritic schists which contributed to the sediments. These clay lenses and 

 balls contain plants. The younger is similar in character, but more uniform, 

 and was evidently deposited in quieter waters, the sands being often argilla- 

 ceous enough to be called clays. 



The older series is correlated with the Patuxent formation of Maryland 

 because of its similar position with relation to the Piedmont ; its practical 

 continuity with that formation in Maryland ; its similar lithological character 

 and its identical flora. The European equivalents are, speaking rather broadly, 

 the Wealden or the Neocomian, Urgonien, and perhaps the Aptian. The 

 younger series of deposits is correlated with the Patapsco formation of the 

 Maryland section, of which it is the southern extension, the brownish argilla- 

 ceous sands of Fort Foote, Maryland, carrying an abundant flora, reappearing 

 across the Potomac at Mount Vernon, White House bluff, Aquia creek, etcetera, 

 exactly similar in character and with an equally abundant and identical flora. 



Tbe European equivalents of the Patapsco formation are the Gault of 

 England and the Albian of continental Europe, the flora of the latter especially, 

 as described from Portugal by Saporta, having not only the same general 

 facies, but containing a large number of similar and several identical types. 

 Speaking broadly, the Patuxent and Patapsco floras are to be correlated with 

 the Glen Rose flora of the Texan region, the Shasta flora of the Pacific coast, 

 the Kootanie of Montana and Canada, the Lakota of the Black Hills region, 

 and the Kome flora of western Greenland. Exact parallels can not be drawn 

 as yet, although it would seem as if the base of the Kootanie (Morrison) 

 should be placed at a slightly lower level than the base of the Patuxent, and 

 that the Shasta flora should be considered as the flora of the upper unequivocal 

 Cretaceous portion of the Knoxville beds. 



The floras of the Patuxent and Patapsco are strikingly different in their en- 

 tirety, but contain many similar elements, their distinctions resting largely on 

 the comparatively large number of dicotyledonous plants which for the first 

 time are found fossil in the Patapsco formation. Much has been written, both 

 fanciful and otherwise, of the primitive Angiosperms of the Older Potomac. 

 This was due in part to the inability of previous workers to differentiate these 



