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

GALLA TIN COUNTY 8 5
thereby making the distance between the
two beds about 100 feet less than the normal
stratigraphic interval. This shortened interval
was taken into account in preparation
of the map.
Because the Pennsylvanian beds are all
equally involved in the folding which produced
the Omaha dome, and because there
was little apparent thinning of these strata
across the structure, it appears that most of
the deformation took place after the deposition
of these beds.
No evidence of displacement has been
found in outcrop in this area except along
the Shawneetown fault which marks its
southern boundary. This fault has been
observed when exposed at times of low
water in the bed of the Ohio river.
The evidence of faulting along other fault
lines mapped consists entirely of drilling and
mine data.
Besides the Shawneetown fault, which is
a zone of major faulting not considered in
this report, the faults or fault zones are the
Ridgeway, Herald, Maunie, and Inman
East, of which only the Ridgeway fault has
been described.lThese are all inclined
normal faults or fault zones. Along each,
drill holes show a shortened section due to
omission of beds.
Along
-
the Kidgeway fault, crossing the
area from north to south and passing a short
distance west of Ridgeway, the strata are
downthrown to the east about 440 feet
(fig. 12 and p1. '7). Its existence as a fault
zone rather than as a sharp monocline" is
established by omission of strata in a drill
hole in sec. 7, T. 8 S., R. 9 E. (No. 165),
which definitely cuts one fault at about
1560 feet and a second at 2600 feet (pl. 7).
The hole starts in Pennsylvanian strata on
the downthrown block and at 1560 feet
passes into the first upthrow block with 55
feet of throw; between 1910-1950 feet it
possibly passes into a second with a throw of
lTacly G. H.. Coal resources of District V (Saline and
. Gallatin lounties): Illinois Geol. Surwy Min. Inv. Bull.
19. plate I. 1919.
20 Cady, G. H., Structure of Herl-in (No. 6) coal bed in
Hamilton, White, Saline, and Gallatin counties, Illinois,
north of the Shamncetown fault: Tlliilois Geol. Sui-vey
Cir. 42, pp. 6-7, map, 1939.
110 feet, and at 2600 feet into the third
with a throw of 230 feet. Just above 2600
feet the drill hole is in strata of the Hardinsburg
formation, and at 2600 feet it
passes into strata of the Paint Creek formation,
which is stratigraphically 230 feet
lower than the Hardinsburg. The upper
and lower faults are definitely determined.
The middle fault is inferred because of the
short interval between the top of the lower
Kinkaid limestone and the base of the
Pennsylvanian system.
Because the hole u7as dry and no others
have been drilled nearby to the west, there
is no means of direct comparison of the
position of Pennsylvanian beds on the two
sides of the fault. Scattered drill holes to
the west (Nos. 340 and 160) indicate that
corresponding key beds are much higher on
the west than on the east side of the fault.
Thus the altitude of No. 6 coal bed is 412
feet below sea level in drill hole No. 165,
whereas in the drill hole in sec. 1, T. 8 S.,
R. 8 E. (No. 340) the coal lies 35 feet
above sea level. What is believed to be
the same fault is cut by several drill holes
about 1~ miles north of Gallatin County
along the east edge of the Roland pool in
sauthern White County.
Proof of the southward extension of the
fault across T. 9 S. is lacking. Earlier maps
have indicated a fault zonez1 in one case, a
sharp fold in another,'\nd essentially no
irregularity in a third,23 depending largely
on the interpretation of four inadequate
drill hole records in sec. 1 (No. 95) and sec.
21 (Nos. 34-36, and 98). The interpretation
adopted here, as shown by the tabu-
lated data, provides the basis for mapping
the fault as indicated. The workings of
the small mine in sec. 13 (No. 67) extend
only a short distance east of the shaft, and
terminate about one-quarter mile west of
the indicated position of the fault. .
'1 Cadp G. H. Coal resources of District V (Saline and
Gallatin Lountiesj : Illinois Geol. Survey Min. Inv. Bull.
19, plate I, 1919.
" Cady, G. H., Structure of Herrin (No. 6) coal bed in
Hamilton, White, Saline and Gallatin counties, Illinois,
north of Sharvneetown failt: Illinois Geol. Survey Cir. 42,
structure map, 1939.
23 Butts, Charles, Geology and mineral resources of the
Eoualitv and Shawneetown area: Illinois Geol. Survey Bull.