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THE QUATERNARY FORMATIONS, 283

Pamlico terrace plain. This escarpment enters North Carolina from
Virginia in the eastern part of Gates County (see Beckford and Eden-
ton quadrangles), and runs in a nearly straight line a little west of
south until it intercepts the coast in the western part of Carteret
County. Its position outside of the areas covered by topographic maps
is known only approximately for the greater part of the distance; how-
ever, Mr. B. L. Johnson has observed the escarpment a short distance to
the eastward of the towns of Grantsboro and Arapahoe in Pamlico
County. Along the crest of this escarpment throughout much of its ex-
tent are accumulations of wind-blown sand in the form of narrow ridges
which probably originated at the time the shore line stood at the foot of
the esearpment’s slope. Reéntrants from the Pamlico plain extend up
the river valleys for many miles as bordering terraces. In many places
the Chowan plain is separated from these estuarine extensions by well-
marked esearpments. Southward of Carteret County the Chowan plain
extends nearly to the coast, being separated from the shore line by very
narrow sirips of the Pamlico terrace. The Chowan terrace plain,
together with the escarpment separating it from the lower-lying Pam-
lico plain, has been traced northward through Virginia into Maryland.

North of Neuse River the materials of the Chowan formation rest
for the most part-upon beds of Miocene age. The estuarine extensions,
however, occur far enough to the west to lap over upon Cretaceous
beds. To the south of Neuse River the underlying deposits consist of
Pliocene, Miocene, Eocene, and Cretaceous strata.

The surface of the formation forms a plain which slopes up from
elevations of about 25 to 40 feet above sea level along its eastern edge
to elevations of about 50 feet along the foot of the escarpment separat-
ing it from the Wicomico plain above. Where it passes up the river
valleys, however, it probably reaches maximum elevations of 70 feet at
the inland extremities of the extensions. In the interstream areas the
plain presents broad, level tracts of land which are swampy in many
places. Green Swamp in Columbus and Brunswick counties is believed
to form a part of this plain. Waccamaw Lake in Columbus County
probably occupies a shallow depression in the plain. Around the edges
the plain has been dissected to some extent by stream erosion form-
ing shallow stream incisions. ‘

The materials making up the Chowan formation consist of sandy
loams, more or less arenaceous clays, sands, and gravels. As in the case
of the Pleistocene formations already described, the coarser materials
oceur at the base and grade up into the finer sands and loams at the
top. In general, the materials are finer in texture than those of the