206 physiography and geology of the coastal plaix provixce. 



Pleistocene. 



The Pleistocene formations already described under the name of the 

 Columbia Group have been recognized over a wide area along the Atlantic 

 seaboard south of the terminal moraine of the last glacial period. The dis- 

 tribution and origin of these deposits along the continent border have been 

 discussed by Dr. G. B. Shattuck.® 



The senior author of this report has recently discussed the correlation 

 of the Pleistocene formations in the Middle Atlantic Coast area. He says :^ 



"The Pleistocene deposits consist chiefly of a series of terraces, the 

 earliest found along the western border of the Coastal Plain, encircling the 

 margin of the Piedmont plateau and the higher elevations of the Coastal 

 Plain, and extending up the estuaries and streams, where it finally merges 

 into fluviatile deposits. This oldest terrace, known as the Sunderland for- 

 mation, can be traced from the glacial deposits southward across Maryland 

 and Virginia into North Carolina. The Sunderland terrace, which has an 

 elevation of 150 to 200 feet along its shoreward margin, declines gradually 

 seaward and toward the larger valleys, where it reaches to below 100 feet in 

 height. Another terrace is found in central and southern Xorth Carolina 

 between the Lafayette and Sunderland and has been named the Coharia 

 formation by Stephenson. 



"The next younger terrace, known as the Wicomico, encircles the preced- 

 ing terrace at a lower elevation, and forms a well marked belt along the 

 eastward margin of the latter although extending up the river channels in 

 some places to the Piedmont border, where it also merges into fluviatile 

 deposits. Its landward margin has an elevation of 80 to 110 feet, from 

 which point it declines seaward and toward the larger stream valleys to 50 

 to 60 feet in elevation. Its surface is not as extensively dissected as the Sun- 

 derland terrace, and near its inner margin are found many buried valleys 

 that were cut at the close of Sunderland time. 



"Below the AVicomico terrace, and encircling it, is the third or youngest 

 terrace of the Pleistocene, which has been called the Talbot. The landward 

 margin of the Talbot terrace is from 40 to 60 feet in height, from which 

 elevation it gradually declines seaward until it reaches nearly, if not quite, 

 to sea-level. The Talbot terrace has been but slightly dissected, compared 

 with the earlier terraces, and forms the coastal lowlands. It may also be 

 traced as a low terrace far up the estuaries and river valleys until it also 



aAiner. Geol., Vol. xxviii, pp. 87-107, 1901: Md. Geol. Survev. Pliocene and 

 Pleistocene, pp. 291, 1906. 



bClark. W. B. Bull. Geol. Soc. Amer., pp. 650, 651 (1908), 1910. 



