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

RICHLAND COUNTY 12 1
nosth-south strike. An indistinct, inter- northward on the LaSalle anticline just as
rupted, and indefinitely bounded belt of
structural depression extends in a line with
a regional trend slightly east of north from
between the Calhoun and Parkersburg oil
dces the dlay City anticline on the west
side of the county.
The structure of the West Franklin limestone
(pl. 11) is nearly parallel to that of
pools to an area south and east of Olney the No. 6 coal bed about 225 feet lower.
in the southern half of the county. It is A comparison of the two structure maps
closed off on the north by convergence on
the EaSalle anticlinal structure.
The beds rise unevenly westward from
this rather indefinitely marked trough to-
(pls. 10 and 11) reveals no indication of
important thickening or thinning of intervening
beds. Since the position of the West
Franklin limestone is somewhat easier to
ward a fairly distinct but mild anticlinal identify in electric logs than that of No.
structure, along which are situated the 6 coal bed, the limestone is useful in picking
Noble, North Noble, and Dundas Consolidated
oil pools, and which has become known
the probable position of the coal bed in such
logs.
as the Clay City anticlinal belt. The Dundas
East, Stringtown, Olney, Olney South, EXPLORATION FOR OIL
and Calhoun pools lie on the east flank of,
AND GAS
but somewhat removed from, the Clay City
anticline on irregular east-west directed The main structural characteristics of the
cross folds of minor importance. These No. 6 coal bed in Richland County have
minor irregularities fail to develop into def- been fairly completely outlined and the definitely
aligned and continuous north-south inite relationship between the distribution
structures parallel to the Noble-Dundas of oil pools in the Mississippian beds and
anticline. Fairly evenly spaced and rela- irregularities in the structure of the coal
tively numerous drill holes in the central bed indicated. However, drill holes are
north-south belt make possible delineation too widely spaced in some parts of the county
of the structure in this portion of the county to eliminate the possibility of the existence
with considerable detail and it seems im- of small pools.
probable that there are any important un- The easternmost tier of townships (R. 14
discovered "highs" along the Calhoun-Dun- W.) has been least thoroughly explored,
das East belt. The general character of the particularly north of the Bonpas pool, but
structure in the county is well established. the generalized structure does not delineate
The Clay City anticline is more abrupt any structures that appear very favorable.
on the west than on the east; the altitude of A good manjT of the scattered small prothe
coal bed falls off about 125 feet toward ducing areas seem as yet to be underdevela
trough-like depression along the boundary oped and additional drilling is to be exbetween
Clay and Richland counties. (See pected. The present map may provide some
Bogota-Rinard syncline in accompany- suggestions as to most suitable directions of
ing report on Clay County, p. 41).
exploration, but in general it is probable that
In general throughout most of the county, a map using smaller contour intervals
the structural relief is in the order of about should be constructed in order to make the
100 feet in the No. 6 coal bed. Because the most of the data available.
"lay" of the beds is relatively even, variations
of only a few feet of relief seem to be
adequate to determine the position of oil
accumulations in the underlying strata.
In the southeast portion of the county, the
Parkersburg Consolidated oil pool (pl. 10)
lies at the north end of an anticlinal structure
which can be traced southward into
Attention should be called again to the
fact that the full record of exploration for
oil is not provided by the present map.
Only drill holes for which electric logs are
available or those logged by Survey field
parties are shos;vn on the map, with the exception
of two cable-tool drill holes, the reco,rds
of which contained some usable in-
Edl~~ards County and which converges formation on the coal resources. The