546 F. BASCOM 
quadrangle), a quartzite ridge, but, as is to be expected in a region 
so near the sea, erosion in subsequent cycles has probably modified 
the Kittatinny surface, notwithstanding the resistant character of 
the rock. 
Near the “‘fall-line”’ where the lowest and oldest formations 
(Patuxent formation) of the coastal plain lie directly upon a pene- 
plained surface of crystalline rocks, the floor which bears them may 
be that part of the Kittatinny peneplain which was submerged, 
was buried beneath sediments, and was thus preserved without 
modification while far inland the peneplain was still developing. 
Fic. 3.—Schooley peneplain in the Reading quadrangle. The summit of Irish 
Mountain in the distance at 1,000 feet represents the Schooley peneplain, as seen from 
a point on the Early Brandywine peneplain, two miles east of Shoemakersville, looking 
south 45° east. 
The Patuxent formation once overlapped the margin of the 
Piedmont province to a distance inland considerably greater than 
is now covered by it; but wherever it has been removed by erosion, 
the surface of the peneplain has been attacked so that the old 
surface cannot be found except perhaps in the immediate vicinity 
of the remnants of the formation. ‘This surface lies at about 180 
feet above sea-level, rising in Maryland to 280 feet. ‘This first 
peneplain, carved on a dissected highland or possibly on uplifted 
peneplains, obliterated in this region all pre-existing erosion sur- 
faces except those that were protected by a cover: an example 
of such a surface is to be found on Paleozoic rocks, where they are 
covered by Triassic formations (see Fig. 4). The later peneplains, 
carved on uplifted peneplains or terraces, never completely obliter- 
ated pre-existing erosion surfaces. 
