subsurface geology and coal resources of the pennsylvanian system ...

GALLA TIN
Succession in road cut on Indiana Highway No. 66
in northwest edge - of Evansville, Sec. 14, T. 6 S.,
I1 W.
Ft. in.
Drift. ........................... 20
Shale, carbonaceous, gray-black. ... 1 2
Coal (Ditney) ....................
Underclay light graj7. ............. 3
11
Shale, gray, silty.. ................ 12
UPPER WEST FRANKLIN LIME-
STONE
Limestone gray, finely crystalline to
dense, ferruginous, massive, weathers
with fairly smooth surface .... 1
Clay and clay shale, dark gray-brown 2
MIDDLE WEST FRANKLIN
LIMESTONE
Limestone light gray, finely crystalline,
nodular, argillaceous, weathers
to small nodules, very fossiliferous. . 6
Clay shale, variegated.. ........... 6
LOWER WEST FRANKLIN
LIMESTONE
Limestone gray, very finely crystalline
to dense, waxy, brown-buff with
smooth surface weathers slabby,
slightly fossiliferous ............... 1
Shale and siltstone, greenish gray. .. 41
11
1
10
COUNTY 71
Succession in Standard Brick Manufacturing Company
Shale Quarry, Sec. 92, T. 6 S., R. 11 W.
Ft.
Siltstone and sandstone, interbedded,
light gray-buff.. ...................... 4 6
UPPER WEST FRANKLIhT LIME-
STONE
Limestone light gray, finely crystalline,
ferruginous, sparsely fossiliferous. .... 1 6
Shale, light green-gray. ............... 2
MIDDLE WEST FRANKLIN LIME-
STONE
Limestone mottled, light gray, nodular,
very fossiliferous ..................... 4
Clay shale, variegated.. ............... 3
LOWER WEST FRANKLIN LIME-
STONE
Limestone light gray, massive, dense,
slightly fossilferous. ................... 4
Shale and siltstone, light greenish gray. . 54
in.
"kick" typical of thin limestone. At the
position of the Shoal Creek limestone the
normal curve is usually off scale (has more
than 100 ohm-meters) ,%nd the third curve
often behaves much like the normal resistivity
curve with only slightly less relief. The
potential curve is usually a straight line, but
occasionally there is a slight positive potential
opposite the resistivity peak at the limestone
(fig. 13).
West Franklin 1irnestone.-The West
Franklin limestone in Gallatin County lies
about 275 feet below the Shoal Creek limestone.
The type occurrence of these beds
is at West Franklin, Posey County, Indiana,
'> but more complete successions of
the beds are to be seen at two localities
near Evansville, Indiana, as observed by J.
N. Payne and the writer in 1943.
The sequence of beds, observed in these
two exposures is similar to that occasionally
5 Ohm-meters described and defined :
Mercanton, P. .L., Regarding resistivity in electrical
prospecting; a practlce to be rejected: from a paper presented
and diqtributed at the Int. Assoc. Terrestrial Magnetism 2nd
IXlec. Wash. Assembly. September 4-1 5. 1939.
a Collett, J., 13th annual report: Indiana Dept. Geol. and
Nat. I-Iist., pp. 61-62, 1884.
7 Schrock, R. R., and Malott, C. A., Amer. Assoc. Pet.
Geol. Bull., vol. 13, pp. 1301-1314, 1929.
found in drill holes in Gallatin, White,
Edwards, Wabash, Richland, and Clay
counties. However, none of the units is
continuous, and one or all the limestone
beds may be absent locally. If so, the only
basis for identification of the West Franklin
zone may be the presence of a variegated
shale (usually red in wet drill cuttings)
at the apprcpriate position or the Ditney
coal bed. There is no known way of identifying
the individual limestone benches
which make up the three benches of the
West Franklin, and it is impossible to tell
with certainty which is present when only
one or two are penetrated. In these studies
the thickest of two benches, or the intermediate
of three benches, is regarded as representing
the thick middle West Franklin
member as developed in the Evansville region,
and measurements are made from this
bench. This procedure is more or less arbitrary
and may not be correct in every case.
There is insufficient evidence to justify the
assumption that the variegated shale always
lies between the 1 x 7 0 lower benches, al-