Union. -Area, 310 square miles; population in 1880, 16,905.
This county extends 20 miles along the West Bank of the West Branch
Susquehanna River, and tapers to 4 miles on the Mifflin County line.
Its south line runs from Sunbury 9 miles to Penn’s Creek, 5 ½ miles
up that creek to Centreville at the east end of Jack’s mountain, and
then 16 ½ miles along the summit of the mountain. The Centre County
line (20 miles) crosses obliquely the 5 great anticlinal ranges of the
Buffalo Mountains to the head of the White Deer Creek, north of which
the White Deer Mountain carries the line east 9 miles. Gregg Township
occupies a piece of the White Deer Hole synclinal. The western side
of the county, therefore, is occupied by seven anticlinal mountain spurs
of Medina sandstone No. IV, dying eastward beneath a low country of
Clinton and Onondaga No. V, across which the river flows, exhibiting
the rock arches in succession. A triple synclinal runs up west between
Jack’s Mountain and the Buffalo Mountains, and along the deepest central
line has been preserved a low ridge of Lower Helderberg limestone No.
VI, for 5 miles west and 3 miles east of Mifflinburg. A loop of No.
VI supporting Oriskany sandstone No. VII runs west from Lewisburg, south
of Buffalo Creek, 5 miles and returns to the river north of the creek.
A small area of Marcellus shale (VIII) lies between the loop and the
river. A third outcrop of VI and VII, 4 miles long, crosses Gregg Township;
and a small area of Marcellus lies north of it. The zig-zag red line
on the map represents the Bloomsburg red shale division of the
Onondaga (V); and between this red line and the edge of the Medina runs
a similarly zig-zagged outcrop of the Clinton fossil iron ore beds as
described already in Snyder County. The mines have been wrought for
Union furnace on the banks of the river 4 miles below Lewisburg, in
1853. Here at the end of Longstown Ridge, at water level, was first
mined the lowest of the Danville beds 20" to 3` thick, with a breast
of 80 yards on a dip of 35º:
southward, the soft ore changing to hard ore at water level; analysis
of hard ore: iron 34; carbonate of lime 39; carb. mag. 2.5; phos.
0.358; sulphur 0.004. In the slope a mile west (dip 45º
; bed 4" to 10") the soft ore goes deeper at the notch, but in the hill
on each side turns to hard ore. Half a mile further west, ore lean,
bed 4" to 6". In Chapel Hollow, 4 miles west of the river, bed rapidly
varies 4" to 18", dip 45º
, breast 80 yards, gangway 800 yards, upper beds thin. Two miles further
west; ravine; lower levels hard ore, upper levels soft; three beds close
enough to be worked together; in all 10" to 12" ore. West of the ravine
the two upper beds each 6" to 10" are worked together; the other is
4". The Price mine is six miles from the river, worked by tunnel: two
lower beds 8" to 12" have yielded 40,000 tons of superior ore. At the
Maize bank they yield 10"; at the Moyer bank 6" to 12". The Kleckner
mine is less than a mile from New Berlin; north of which the Colton
mine is on a 3" to 6" bed; and a mile west of it Seabol’s mine has
4" to 6" of soft ore; but further towards Centreville are no mines.
This account of the fossil ore on its southernmost outcrop in this county
will serve for a description of it on other outcrops.
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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