92 THE PLIOCENE AND PLEISTOCENE DEPOSITS OF MARYLAND 



escarpment. The few deposits of Lafayette materials which may possibly 

 underlie the Sunderland are therefore disregarded because unrecogniz- 

 able. Similarly the Wicomico is described as including all the gravels, 

 sands, and clays overlying the pre-Laf ayette deposits and extending from 

 the base of the Sunderland-Wicomico escarpment to the base of the 

 Wicomico-Talbot escarpment. It is possible of course that materials of 

 Lafayette and of Sunderland age may occasionally lie beneath the 

 Wicomico formation, and the same may again be true of the Talbot for- 

 mation. 



The Wicomico Formation. 



The name Wicomico, suggested by the Wicomico river, in St. Mary's 

 and Charles counties, was first proposed by the author in May, 1901. It 

 is equivalent to the older portions of Darton's Later Columbia as de- 

 scribed and mapped by him in the Washington folio, IT. S. Geological 

 Survey, 1901. To the north in New Jersey there is no single formation 

 described to which it is equivalent, but it corresponds to portions of 

 Salisbury's Cape May, Pensauken, and possibly Bridgeton. 



Areal Distribution. — The Wicomico formation extends from South 

 Amboy across southern New Jersey into Pennsylvania, Delaware, Mary- 

 land, and Virginia. Beyond this point it has not been studied carefully, 

 but from facts which have been gathered it appears to extend far to the 

 southward. In the Coastal Plain of Maryland it has a greater areal 

 development than either the Lafayette or Sunderland. It has been less 

 dissected by erosion and, therefore, shows the plain terrace character of 

 its surface far better than either of the other two formations. Its great- 

 est development is on the Eastern Shore (Plate I) where it forms the 

 water shed down the center of the region and extends as far south as 

 West in Worcester county. On the Western Shore its development is not 

 so continuous. It forms a border beneath the Sunderland on Elk Neck 

 as well as along the western side of Northeast river. South of here it 

 is developed in irregular outliers and in southern Maryland it forms a 

 fringe about the Sunderland deposit and veneers the bottom of ancient 

 stream valleys which formerly drained it. 



