CORRELATION OF THE VIRGINIA COASTAL PLAIN 



FORMATIONS 



The geological formations of the Virginia Coastal Plain are closely 

 related to those found in the adjacent states of Maryland and North Caro- 

 lina and there is not a single formation in the State that cannot be traced 

 into adjoining states and in some instances even over a wider area. 

 Most of the formations are fossiliferous, some of them containing a great 

 profusion of the remains either of animal or plant organisms. It is possible, 

 therefore, in most instances to correlate the formations by the use of pale- 

 ontological criteria. The Patuxent, Patapsco, Aquia, Xanjemoy, Calvert, 

 St. Mary's, and Yorktown formations can all be correlated on this basis, 

 while the later Lafayette and Columbia formations can only be satisfactorily 

 correlated on the basis of physical criteria since the animal and plant 

 remains found in the Talbot formation, although clearly of post-Tertiary 

 age, are yet inadequate to separate the Talbot from the otlier Pleistocene 

 formations. 



CRETACEOirS. 



The formations of Cretaceous age found in Virginia can be correlated 

 with Cretaceous deposits elsewhere on the evidence of both lithology and 

 paleontology. The Lower Cretaceous formations, which alone appear at 

 the surface, afford much more satisfactory evidence for detailed correla- 

 tion than do the Upper Cretaceous which have been observed only in deep- 

 well borings far to the east of the other Cretaceous outcrops. Dr. L. W. 

 Stephenson and Mr. E. W. Berry, under the direction of Dr. T. ^A"ayland 

 Vaughan, have greatly enlarged our knowledge of the stratigraphy and 

 paleontology of the South Atlantic and Gulf States, and the results of their 

 work have been available for the comparisons with the southern districts 

 south of North Carolina. 



Lower Cretaceous. 



The Lower Cretaceous formations of Virginia which liave been already 

 described under the name of the Potomac Group comprise part of the belt of 

 Lower Cretaceous deposits which have been found over a wide area along 

 the eastern border of the continent. 



