tA 
214 The Americati Geologist. April, i89v» 
The Piedmont belt of Virginia has been described by a 
number of observers in recent years. McGee writes: — "The 
plain is not monotonously smooth ; here it undulates in grace- 
ful swells, there it dips into rocky river gorges, winding across 
its width. . . Such is the Piedmont plain within view 
of Monticello and such is the province throughout its extent 
from New York to Alabama" (Nat. Geogr. Mag., viii, 1896. 
261). The Piedmont rivers "rush through narrow, rock- 
bound gorges. . . . All the Piedmont rivers, large and 
small, are incessantly corrading their beds" (Ibid.. 262). The 
plain "must be regarded as the basal portion of a vast mass 
of inclined rocks of which an unmeasured upper portion has 
been planed away" (Ibid., 263). In describing the same re- 
gion, Darton writes: — "The Piedmont plateau is a peneplain 
of Tertiary age . . . the plain has been deeply trenched 
by drainage ways, but Vvide areas are preserved on the di- 
vides" (Chicago Journ. of Geol.. ii, 1894. 570). He believer 
that this peneplain, AB. fig. i. continues across the inner 
strata. BC, of the coastalplain. and that it should therefore be 
distinguished from an earlier peneplain carved on the same an- 
cient rocks, part of which is BE. preserved beneath the strata 
of the coastal plain, and part of which, DB, is generall\- 
hereabout destroyed by erosion. It is upon the older peneplain 
that the Potomac formation, with its fossil terrestrial flora, di- 
rectly rests. Keith gives an elaborate account of a part of 
the Piedmont plain in his "Geology of the Catoctin Belt" 
(14th Ann. Rep. U. S. G. S.), and discusses its relations to 
various members of the coastal plain series. 
Any one who will follow up the foregoing references, or 
who will, better still, look over the region on the ground., 
will find a decidedly larger portion of the peneplain surface 
preserved than is the case in New England or New Jersey: 
and this is most natural, for the Mrginia Piedmont plain is of 
distinctly later origin than the peneplain of the uplands fur- 
ther north: the latter corresponds to the earlier peneplain. 
DBE, in Virginia. But it is not only the comparative con- 
tinuity of the Piedmont plain that makes it a valuable ex- 
ample: the deep soils of the upland plain and the rocky walls 
of the narrow steep-sided valleys are as important witnesses 
to the once lower position of the plain and to the uplift by 
