The Potter journal. [volume] (Coudersport, Pa.) 1857-1872, 1861-02-21
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mirable Report of Prof Rogers already
| alluded TO- it viii be seen that the VIZ ole
of Pennsylvania west of the Allegheny
mountains is naturally divided by the
broad wave-like bases of all the strata un
derlying the coal measures, into six dis
tnct basins or rather synclinel trodshsi
trenching through the State in N. h:
and s. w: direction, nearly PARALLEL with
the most westerly range of the Allegheny
mountains. Five of these troughs are
long narrow extensions, and holding in
their depressions the several successive
groups of the coal measures. The sixthj
and by far the largest, embraces all the
country from the outcropping of the Fer-
gent and Cadent formations, along the
Inc of the headwaters of Lake Erie. od
the North West to the line of anticlirel
elevation between the fifth and sixth ba-
sins; running through about the middle
of Mexican, Forest and Clarion counties
on the South East. The dip OF the Yer
gent aud Cadent strata from their out
crop on the North West near Lake Erie;
10 the centre line or lowest depression of
the trough is about fourteen feet to the
mile, while the counter dip, or that from
! the anticlnel line on the South East, to
the same line of depression, is near two
! hundred feet to the mile. This brings
the lowest part of the basin or trough
much nearer to the South East side. Con-
sequently the main axis Of this basin,
passes in North East and South West
direction, between Mexican and Warren
counties, and through the eastern part of
Venango county, following Tionesta creek
in part of its course, and crosses the
Allegheny river not far from the mouth
of the Clarion. As the trough tends
south westward, the Vergcnt and Cadent
rocks, continually dip beneath the con-
stantly thickenng coal measures, and do
not appear again in that direction till they
emerge in Kentucky and Tennessee.
Corresponding with this, it may ID
noticed by any one, that the hard con-
glomerate sandstone which appears at the
mouth Of French creek high in the hills;
sinks down to the water level at the juno
ton of the Clarion with the Allegheny
river; and the same also rises again be.
twee1 there and the Red Bank Creek.
Consequently the geological dip exceeds
the geographical fall between French
creek and the Clarion river, by some
more than hundred feet.
Precisely how much this peculiar struc..
ture has to do with the distribution Of
the Gil contained in this region, cannot
yet be fully known. But it will be seen
that the geographical slope of the country
comedies, on the larger side of the basin,
with the dip of the strata containing the
oil, which condition must give direction,
not only to fluids flowing on the surface
but also to fluids circulating within the
veins and assures of the rocks. Accord
ingly the deep valley of the Allegheny
river lies everywhere, from its entranc6
into Pennsylvania to little below the.
Clarion river within the central range of
this trough, and in part of its course,
near or Immediately in the axis of the
lowest depression. The same range also
will include all the oil thus far success
fully worked.
The outlying troughs of Ohio, and the
anticlined valleys of Virginia, are inde-
pendent divisions, which with the similar
extensive basin of Kentucky may, per-
haps, be further considered.