GENERAL GEOLOGY OF BURGETTSTOWN QUADRANGLE. 39 
determining the structure of the rocks than any other member 
except the Pittsburg coal. On the east side of the quadrangle, south 
of the Pittsburg, Cincinnati, Chicago and St. Louis Railway, the 
Bulger limestone is an excellent guide as far south as Cherry Run, 
also through the southern part of Mount Pleasant Township. In 
the western part of the quadrangle south of the railroad the Dins- 
more is more prominent than the Bulger limestone, but the latter 
is present, and was used in many places. 
Many comparisons of elevations were made for determining: the 
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distance of these two beds above the Pittsburg coal, with the follow¬ 
ing results: In Jefferson Township the Dinsmore bed is 138 feet 
and the Bulger bed 167 feet above the base of the Pittsburg; coal; in 
Smith Township the Dinsmore bed is 132 feet and the Bulger bed 
155 feet above; in Mount Pleasant Township the Dinsmore bed is 
140 feet and the Bulger bed 165 feet above. 
The It aynesburg coal, at the top of the Monongahela formation, 
maintains a fair thickness in all parts of the quadrangle except in the 
central part of Mount Pleasant Township. This coal is in Smith 
Township, 264 feet; in Mount Pleasant Township, 270 feet; and in 
Jefferson Township, 278 feet above the base of the Pittsburg coal. 
In the Claysville quadrangle, south of Burgettstown quadrangle, 
this interval was determined from well records to be about 290 feet 
near the north edge. In view of this fact an interval of 285 feet 
was used along the south edge of the Burgettstown quadrangle. 
In the Washington formation the Waynesburg “A” and “ B ” coals 
are guides to the stratigraphy. They were, however, little used for 
determining the surface structure except in a limited area east of 
Hickory. 
*/ 
The Washington coal is the best marker between the Waynesburg 
coal and the Upper Washington limestone. This coal was used 
largely in determining the geologic structure in the middle of the 
southern half of the quadrangle. The distance of the Washington 
coal above the Pittsburg coal in Smith Township was determined by 
well records to be 364 feet. In Mount Pleasant Township the 
Washington coal averages 108 feet, and in Cross Creek Township 
107 feet above the Waynesburg coal. 
PROBABLE ERRORS IN MEASUREMENT OE INTERVALS. 
An examination of the results of these measurements shows a 
gradual increase in the intervals from north to south. This increase, 
however, is not large enough to demand the averaging of measure¬ 
ments taken in different parts of any one township. 
In the measurements of the distance between the different strata, 
a range of 20 feet was found in the intervals. This range was 
