SUBAERIAL DIVISION. 51 



a height of less than 10 feet. It is very prominent just to the west of the 

 Dismal Swamp and in many places in the valleys of the estuaries. The 

 Talbot terrace occupies practically the entire counties of Mathews, Elizabeth 

 City, Norfolk, and Princess Anne on the AVestern Shore and all of the 

 Eastern Shore. It is found also as a bordering terrace, more or less con- 

 tinuous, along most of the estuarine portions of the Potomac, Eappahan- 

 nock, York, and James rivers. It has suffered less from erosion than any 

 of the other terraces, because of its lower altitude and more recent forma- 

 tion, and maintains nearly everywhere its original surface almost unmodi- 

 fied by the present drainage. 



The Talbot terrace although in general monotonously flat, contains some 

 shallow depressions, the most noted of which is that occupied by the Dismal 

 Swamp. In other places, especially on the Eastern Shore and in Princess 

 Anne County, the surface has been rendered more or less irregular by recent 

 sand dunes. The altitude of the Talbot terrace, where it abuts against the 

 Wicomico terrace is usually about 40 feet. From its landward margin it 

 slopes away toward the surrounding waters where it either terminates in a 

 wave-cut cliff or else passes down to tide level and merges with the modern 

 beach. 



Rccfnt ti mice. — The lowest or Recent terrace is almost entirely eon- 

 fined to the submerged portion of the Coastal Plain. It is in process of 

 formation in the large estuarine streams and in Chesapeake Bay and is 

 continuous with the submarine portion of the Coastal Plain previously 

 described. Wave action and currents are furnishing materials that are being 

 deposited along the margin of the present shores. Parts of this terrace are 

 submerged beneath many feet of water while other portions are only sub- 

 merged during times of high tide. These latter areas constitute the tide- 

 water marshes which are so well developed along the short e-tuaries on 

 eitlier side of Chesapeake Bay and occasionally from large areas several 

 square miles in extent along the larger estuaries many miles distant from 

 the Bay. These marsh areas are constantly being built up l^y the annual 

 accumulations of vegetable debris and also receive mud deposits during 

 seasons of flood. Other portions of the Eecent terrace receive the sediments 

 brought down by the streams and also in places the accumulation of oyster 

 shells. Could the Eecent terrace be exposed, there is no reason to believe 

 that it would appear essentially unlike that of the Talbot. It would be a 

 monotonously flat plain with gentle slopes toward the channels of the present 

 estuaries and separated in many places from the Talbot by a low escarpment. 



