Clinton. - Area, 860 square miles; population in 1880,
26,278. Two thirds of this county spreads itself over the Allegheny
Mountain plateau (2000`A.T.,) and is profoundly trenched by the winding
gorges of the Susquehanna River and its branches; Tangascootac Creek,
Holland’s, Backer’s, Hall’s, McSherry’s, Fish Dam, and Burn’s Run
entering it from the west; Queen’s, Lick, Rattlesnake, McGingley’s,
and Hyner’s runs from the east; Youngwoman’s Creek, Paddy’s, Drury’s,
Shintown, and Cook’s runs, and Kettle Creek from the north; and Grove,
Birch Island, and Loop runs from the north-west. The Ninemile canon
of Kettle Creek is one of the grandest pieces of river erosion through
horizontal sandstone strata in the State. Very little of the coal-measure
beds has escaped destruction, and only in small isolated patches on
the very highest mountain divides, a thousand feet above the river
beds. Although they look to be scattered at random about the map,
they are in reality arranged along the lines or belts, representing
three very shallow basins, which cross the county from S. W. to N.
E. In the walls of all these mountain valleys crop out the horizontal
edges of Formations XII, XI, X, and IX, and even the Chemung No. VIII
is exposed in the bend at Youngwomanstown. The southern third of the
county presents a very different scene. In front of the Allegheny
Mountain wall, crowned by XII, and terraced by X and IX, with foot
hills of VIII (Chemung, Portage, Genessee, Hamilton, Marcellus,) lies
the deep valley of the Bald Eagle Creek, excavated along the outcrops
of the Lower Helderberg limestone VI, and Onondaga and Clinton shales
V. Into this valley the mighty Susquehanna River breaks through a
noble gap, turns east, and flows away in broad meanders towards Williamsport.
The valley is hemmed in on the south by the vertical rocks of IV (Medina
and Oneida sandstone,) making the straight Bald Eagle mountain, through
a gap in which flows (northward) Fishing Creek, draining the head
of Nittany Valley; and through another gap, McElhattan’s run. The
gap through which Nippenose Valley is drained lies in Lycoming County.
Wayne, Greene, and Crawford townships make a broad flat arch of No.
IV, uniting the Bald Eagle and Nittany Mountains, between which Nittany
Valley lies, with its side slopes of No. III slates; and its floor
of No. II limestone; and its middle ridge of barrens, charged with
brown hematite-iron-bearing sands and clays. The west of Nippenose
Valley projects into Clarion County, and is the exact equivalent of
Nittany Valley. Sugar Valley, an anticlinal repetition of Nittany
Valley, runs along the southern county line. The intermediate valley
of Cherry Run, on the contrary, is a synclinal trough in which a strip
of No. V has been preserved.
From: A geological hand atlas of the sixty-seven
counties of Pennsylvania :embodying the results of the field work
of the survey, from 1874 to 1884. By J. P. Lesley. (Report of
progress (Geological Survey of Pennsylvania), v. X ) Harrisburg, PA
: Board of commissioners for the second geological survey, 1885.
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