76 Hayes and Campbell—Appalachian Geomorphology. 
as a working hypothesis, traces of a baselevel can be found 
in places that otherwise afford no evidence of its existence; 
a terrace cut here and a wind-gap there serve to locate the 
plain so that it can be restored and contoured with consider- 
able confidence. The restored surface corresponds with the 
summits of the ridges at Harpers Ferry, where proximity to the 
Potomac insured complete reduction to baselevel and afforded 
opportunity for subsequent erosion to almost completely dissect 
the plain. On either side, away from the river, the crests become 
more irregular, and evidently stand above the peneplain, while 
the present wind-gaps show traces of baseleveling, and probably 
correspond in altitude very nearly with the plain. On the east- 
ern side of the Blue ridge throughout North Carolina there is 
but little data available for reconstructing the Cretaceous pene- 
plain. The present writers are personally unacquainted with 
the region and a large part of it has never been mapped with 
contours. At only one point has the phenomenon of baselevel- 
ing been recognized. Kerr has described certain topographic 
features observed in the vicinity of Morganton, North Carolina,* 
and likened them to the Asheville baselevel. His theory as to 
their glacial origin cannot be accepted, but from his description 
it may be inferred that the valley of the Catawba river has been 
baseleveled to about the same extent as the French Broad at 
Asheville, and that the plain has been nearly as well preserved. 
Its altitude here is 1,400 feet, so that it mu&t have a very rapid 
ascent toward the west in order to reach an altitude of 2,400 or 
2,500 feet at Asheville, which is only fifty miles distant. This 
sharp ascent of the Cretaceous peneplain on the eastern slope 
of the Blue ridge dies out rapidly southward, partly through 
the flattening out of the fold in that direction and partly through 
the influence of a cross-axis of depression in the vicinity of 
Atlanta. 
Southern marginal Type.—In the region southwest from Atlanta 
as far as the Coosa river the present attitude of the peneplain 
differs from that in any other portion of the province. In this 
region the baseleveled plain has suffered but little uplift from 
the position in which it, was formed, and this slight- elevation 
has taken place in very recent geologic time. Hence the pene- 
plain is well preserved and many of the present streams, as the 
* Origin of new Points in the Topography of North Carolina, by W. C. 
Kerr: Am. Jour. Sci., 3d series, vol. xxi, 1881, pp. 216-219. 
