202 PHYSIOGRAPHY AXD GEOLOGY OF THE COASTAL PLAIX PEOVIXCE. 



The Trent and Castle Hayne formations are younger than the Virginia 

 Eocene formations and evidently represent the Jackson and possibly in part 

 the upper Claiborne as well. A more exhaustive study of the fossils is 

 necessary before an exact correlation can be made. 



Tahh of Eocene Formations. 



Miocene. 



The Miocene formations of Virginia are in part continued into Mary- 

 land** and Delaware on the north and in part into North Carolina on the 

 south. The senior author in discussing the formations in this district says.* 



"The Miocene deposits are best developed in the Chesapeake Bay region, 

 where four formations have been recognized^ known as the Calvert (clays, 

 sandy clays, diatomaceous earth, shell marls), the Choptank (sandy clays, 

 sands, shell marls), the St. Mary's (sandy clays, sands, shell marls), and 

 the Yorktown (fragmental shell marls, sandy clays, sands). The Choptank 

 does not occur in Virginia, and the Yorktown is absent in Maryland. These 

 formations are evidently continued in part into Xew Jersey, as similar 

 faunas have been found there, but the relationships have not been fully 

 worked out as yet. To the southward the St. Mary's and Yorktown forma- 

 tions, transgressing the earlier deposits, continue on into North Carolina, 

 both being found over extensive areas to the north of the Hatteras axis, 

 where the Yorktown overlies the St. Mary's unconformably. To the south 

 of the Hatteras axis deposits very similar to the Yorktown formation, both 

 lithologically and paleontologically, but known under the name of the Duplin 

 formation, are found resting unconformably on pre-Miocene formations." 



a Clark, Shuttuck, and Dall. Md. Geol. Survey, Miocene. 1904. 

 6 Clark, W. B. Bull. Geol. Soc. Anier., Vol. xx. p. 649, 1908. 



