McKean. - Area, 1,000 square miles; population in 1880,
42,565. This is a square district 38 miles long upon the New York
State line, by 27 wide on the west county line of Potter. The branching
heads of the Allegheny river gather the rain-fall of its eastern half
to flow northward into New York at Olean; the small water-tree of
the Tunianqwant (Potato creek) does the same for Bradford and Lafayette
townships, while the western townships shed their streams into Warren
county, especially by the Kinzua and Tionesta valleys. Innumerable
ravines descend in all directions from the flat and narrow divides
into which the now deeply-sculptured table land is broken up, lying
at a general level of more than 2,000` A.T., and the steep slopes
of these ravines are cliffed and terraced by the lower coal measures,
the three divisions of the Conglomerate No. XII, the thin underlying
shales, the massive sand-rocks of No. X, and the softer shales and
sandstones of No. IX. The foot slopes and valley beds of all the main
water-courses are composed of the upper beds of the Chemung formation,
far down in which lie the sands of the Bradford oil field. The highlands
are covered with what remains of the Lower Productive coal measures,
nowhere more than 140`, holding a coal bed 1` thick; 40` under that
the Dagus coal bed 3`, opened only at two places; 10` to 30` below
that the Ferriferous limestone 4` to 8` thick at Clermont, and 30`
below that the Clermont coal bed 3` thick. The Alton coal beds (upper,
2` to 3 ½`; middle, 4` to 8`; lower 4`) mined at Alton, Clermont,
and elsewhere, lie between the Upper (Johnson’s Run sandstone) and
Middle (Kinzua Creek sandstone) divisions of the Conglomerate No.
XII. The Marshburg coal bed between the middle and bottom divisions
of XII, and lying 170` beneath the Ferriferous limestone, has been
opened at several places, but never much worked, being thin and poor.
The bottom division of XII (Olean round-pebble conglomerate) caps
the high ridges along the New York line, and makes picturesque "Rock
cities" (pictures of which are published in Report R, plates 1 to
6.) It varies from 25` to 50`, and under it lie red and blue shales
varying from 40` to 70`. Sometimes a bed of black slate or poor coal
bed underlies the Conglomerate. Beneath the shales lie Sub-Olean (flat-pebble)
conglomerate, very uniformly 40` thick, making fine ranges of cliffs
along the Kinzua valley, for example at Ludlow station on the Phila.
and Erie railroad (1,604`A.T.) Beneath it are other Pocono sandstones
and shales, near the bottom of which lies the Marvin Creek limestone,
exposed along Shephard run in southern Bradford (2` thick), and on
the west slope of Chappel hill in northern Sergeant (5` thick), and
elsewhere, or traceable by its fragments pitted with the indistinct
casts of fossil shells, or by limewater springs and deposits of tufa,
as on the Warren road 6 miles west of Smethport. The dip of the formations
is scarcely perceptible southwards, and the Pocono formation (X) thickens
in that direction, thus: at Smethport 250`, at Norwich 300`, at Keating
station 400`, at Shippen 450`, at Emporium 550`, at Driftwood 700`,
at Sinnemahoning in Cameron county 750`. This fact is important to
those who bore through to reach the Bradford oil, for their trial
wells must be proportionately deeper the further south they locate
them. The Catskill formation (IX) varying little from 250` in thickness
in the western and central townships, thickens to 334` at Ridgway
(Elk County), to 347` in the Cameron well (Cameron County), and to
370` at Coudersport (Potter County.) The Chemung (VIII) upper
shales and soft sandstones are 1,282` thick at Bradford, 1,305` at
Smethport, 1,300` at Wilcox (divisible into 350` upper gray shale,
300` middle red shales, * and 650` lower gray shales.) The Chemung
middle gray sandstone and shale beds, 650` thick, make the famous
Bradford Oil-Sand Group of the drillers shown in the Dennis
well thus: gray s. and sl. 36; 1st sand 25`; gray
s. and sl. 44`; gray sl. 175`; brown s. 17`; sl. 28`; 2nd
sand 36`; gray sl. And some s. 283`; 3d sand (the only
productive Bradford oil sand, although the other two have produced
some "slush oil" at one place) about as coarse as ordinary Jersey
Shore sand, loosely cemented, averaging 45` in thickness, and so much
alike under an area 18 miles long (N. 30º
E.) and 12 miles wide, that 98 out of every 100 wells have been productive.
The first well drilled by the Deans in 1865 at Custer City, only 900`,
was abandoned, because the "3d sand" (then unknown) lies 1,130` beneath
railroad grade. The first Tarport well (605`) was also stopped 400`
too soon. The first Barnsdall well (begun in 1862) at Bradford village
was deepened in 1866 to 975`, 150` short of the sand. The "3d sand"
was discovered November, 1871, by the first Foster Oil Co. well, 2
miles N.E. of Bradford, at a depth of 1,110` ("slush oil" at 751`),
producing 10 barrels. Three years later the Butts well No. 1, 2 ½
m. N.E. of Bradford, started off December 1874 with 70 barrels, and
inaugurated the wonderful later history of the region. By April, 1880,
4,000 producing wells were yielding 50,000 barrels per day, i.e. five
sixths of the total oil production of Pennsylvania that month.
The total production of the years 1877-1882 (inclusive) was 85,866,000
barrels. (See Carll’s chart in Report III Atlas), in 1883, 13,235,000;
and in 1884, 11,682,000; in all 110,783,000 barrels. The geyser well
near the Mountain House hotel at Kane, and the Wilcox spouting well,
are described in Report R, pp. 246, 248.
* Mansfield fossil ore beds of Tioga and Bradford counties?
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.
Return to Geologic
Maps of Pennsylvania Counties
Copyright © 2000, Pennsylvania State University
Libraries. All rights reserved.
Please send comments to: ems@psulias.psu.edu
Last modified: 5/3/01
|
