GENERAL GEOLOGY OF 1 STEUBENVILLE QUADRANGLE. 27 
GEOLOGIC FEATURES SHOWING AT THE SURFACE.® 
SECTION OF ROCKS EXPOSED. 
Upon the surface of the Steubenville quadrangle are exposed strata 
that represent a vertical section of over 1,000 feet in the Pennsyl¬ 
vanian series. This section consists of a part of the Washington, all 
of the Monongahela, Conemaugh, and most of the Allegheny forma¬ 
tions. The Lower Kittanning coal of the Allegheny measures comes 
to view along Ohio River in the northern portion of the quadrangle, 
while the Washington coal of the Washington formation lies near the 
top of the highest hills in the southeast corner of the quadrangle. 
Between these two limits are a number of beds that are easily recog¬ 
nizable and of use in determining positions within the geologic sec¬ 
tion. Most prominent among these are the Ames limestone, Pitts¬ 
burg coal, Meigs Creek coal, Benwood limestone, Uniontown coal, and 
Wavnesbunr coal. 
KEY HORIZONS. 
The base of the Pittsburg coal has been taken as the horizon upon 
which to represent the geologic structure at or near the surface. This 
important bed outcrops in all portions of the quadrangle except in 
an area east of New Cumberland, where an anticlinal dome has raised 
its horizon a couple of hundred feet above the highest hills and the 
coal bed has been eroded. 
The Ames limestone of the Conemaugh formation exceeds the Pitts¬ 
burg coal in its area of outcrop. This limestone and the Pittsburg 
coal have furnished most of the information for the plotting of the 
surface structure. The Lower Kittanning coal was used along Ohio 
River in the northern half of the quadrangle, and the Sewickley 
(Meigs Creek) coal in some portions of the southern half. 
In order to make use of these beds in determining the geologic 
structure of the Pittsburg coal, careful measurements were made of 
the intervals between them in as many places as was possible. 
MEASUREMENT OF INTERVALS BETWEEN KEY HORIZONS. 
The interval between the Pittsburg and the Lower Ivittanning 
coals was not obtained by direct measurement. The distance of the 
a jjj this paper the names of oil sands and other beds that are known only through the 
exploration of the drill are those commonly used by the well drillers. Many of these 
names are fanciful, but they have come into common use throughout the oil fields, and 
for that reason are used in this report. In most cases the equivalent geologic names are 
also given, so that the reader is enabled to correlate with the same beds where they show 
in outcrop. 
