402 THE COASTAL PLAIN OF NORTH CAROLINA.

EDGECOMBE COUNTY.

Topography.—Portions of three Pleistocene terrace plains make up
the surface of this county. The Chowan plain at elevations of 30 to 60
feet borders Tar River in a belt 4 to 8 miles wide on the east and north
along its entire length in the county; the Wicomico plain at elevations
of 60 to 100 feet covers a belt a few miles wide in the eastern and
northeastern part of the county and has a limited development along
the west and south side of Tar River; the Sunderland plain, with ele-
vations ranging from 110 to 135 feet, covers the greater part of the
area west and south of Tar River, and is also present in the northern
part of the county. In many places these plains are separated from
each other by well-defined scarps. They are all dissected in greater or

   
  
  
 
 
 
 
 
 
 
 
   
 
 
 
 
   
  
  
 
  

lesser degree by stream erosion.
Geology.—Granite rocks outcrop in the bed of Tar River in the
vicinity of Rocky Mount. The bedrock, consisting of these granites
and other crystalline rocks, dips gently to the eastward, becoming
deeper beneath the deposits of the Coastal Plain. At Tarboro, erystal- _
line schists were encountered in a well at a depth of 328 feet. Over
the central and eastern portions of the county the compact, arkosic, mi-
caceous sands and drab clays of the Patuxent formation rest upon the
eroded surface of the erystallines, attaining a maximum thickness of
about 290 feet at Tarboro, as shown by the deep well at that place. The
upper undulating surface of the Patuxent formation rises and falls a
few feet above and below water levek along Tar River. Overlying the
latter, and overlapping and transgressing still farther westward upon
the crystalline rocks, is the Miocene, which consists in the main of strati-
fied sands, clays, and shell marls, but along the base is made up in part
of greenish, gravelly, lignitic sands and dark, lignitic, laminated clays.
Pleistocene loams, sands, and gravels of the Sunderland, Wicomico, and
Chowan formations blanket all older formations over the entire county.
Water Resources.—In this county the Pleistocene formations furnish
most of the water for domestic use. Open and driven wells 12 to 30
feet in depth yield water from the lower sandy or gravelly portions of
the terrace deposits. So compact is the sandy loam at the surface that
in many places the open wells require no curbing to keep the walls
Be intact. Along the stream slopes and scarps there are many springs of
aa small size. These are but little used.
* _ At Turnage, open and driven wells 8 to 25 feet deep are used. The
water from the driven wells is reported ferruginous. Many of the
deeper open wells enter a bluish clay containing roots and vegetable

 

 

 

 

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