CfeETACEOUS FLORAS OF VIRGINIA AND NORTH CAROLINA 665 



GEOLOGIC RELATIONS OF THE CRETACEOUS FLORAS OF VIRGINIA AND 



NORTH CAROLINA 



BY EDWARD W. BERRY * 



[Abstract] 



Contents P age 



Introductory 655 



The Lower Cretaceous of Virginia — its correlation and flora 655 



The Upper Cretaceous of Virginia 657 



The Lower Cretaceous of North Carolina and its correlation 657 



The Upper Cretaceous of North Carolina and its correlation . . 658 



Introductory 



The Cretaceous of the Atlantic Coastal plain may be readily divided into two 

 series of deposits — an older estuarine series of clays, lignites, conglomerates, 

 and arkosic cross-bedded sands and a younger marine series of mostly glau- 

 conitic sands. The older attain their best development in Maryland, while the 

 younger are more differentiated in New Jersey, although they attain a greater 

 thickness in the extreme southern Coastal plain. The older deposits abound in 

 fossil plants, while the younger contain an abundant marine, largely inverte- 

 brate, fauna. The transitional beds intercalated between these two series of 

 deposits have consequently a flora more or less closely related to that of the 

 older deposits, while their fauna is more or less closely related to those of suc- 

 ceeding deposits, which facts offer an excellent opportunity for differences of 

 opinion regarding their exact equivalence. These older deposits are found 

 overlapping the eastern border of the Piedmont rocks along the so-called "fall 

 line" from Delaware to Alabama, but are largely covered by the landward 

 transgression of the much later Tertiary deposits, especially in the region from 

 Fredericksburg, Virginia, to Fayetteville, North Carolina, and again in north- 

 eastern Georgia. 



The Cretaceous deposits of Virginia have been definitely known since the 

 days of Rogers and have been the subject of a voluminous literature. Those of 

 North Carolina have been but recently studied, and are about to be described 

 by Dr L. W. Stephenson, of the United States Geological Survey. The writer 

 collaborated in considerable of the field work, and also had the privilege of 

 studying the fossil plants which were collected. The present brief communi- 

 cation is presented more for the purpose of acquainting geologists with the 

 work in progress than it is to record finished results, in consequence of which 

 a detailed statement is avoided. The three most interesting geologic questions 

 are those of age — that is, correlation, segregation, and paleobotanic features — 

 and in all three categories the present conception differs very materially from 

 those which have gone before. 



The Lower Cretaceous of Virginia — its Correlation and Flora 



These deposits coincide with the beds which Professor Marsh insisted were 

 Jurassic in age and which Professor Ward divided into four formations 

 (James River, Rappahannock, Mount Vernon, and Aquia), and from which 



1 Introduced by W. B. Clark. 



LXII — Bull. Geol. Soc. Am., Vol. 20, 1908 



