598 CHARLES S. PROSSER 
Total 
No. Thickness Thickness 
Feet Feet 
has a zone of marcasite at the base and it appears to | 
be more or less common throughout the entire thick- 
ness. In the small gorge where the run cuts through 
the formation its entire thickness is shown on each 
side which varies from 1 ft. 11 in. to about 7 ft. 6 in. 
Its under surface is uneven, apparently correspond- 
ing to the inequalities in the upper surface of the 
underlying shale. The under surface of the Berea as 
shown on the western bank is decidedly irregular. 
From the point where the sandstone is lowest its 
base, or the top of the Bedford as it is followed up 
stream, rises 3 ft. 10 in. in a horizontal distance of 
21 ft. At the lower end of the cliff where the sand- 
stone has been exposed in recent years by a landslide 
the base of the Berea rises rapidly from its lowest 
point to a height of 5 ft. 8 in. and the sandstone is 
apparently reduced to a thickness of 1 ft. rr in. In 
the small gully entering this gorge of Smith Run, just 
above the western cliff, the Berea is only 2 ft. 7 in. 
thick; while about 36 ft. farther west on the eastern 
bank of Smith Run it is about 74 ft. thick. In all 
these outcrops it is the lower part of the Berea which 
thins and thickens, since the upper surface appar- 
ently remains uniform with the black Sunbury 
shale generally shown resting on it. There is no 
tendency to concretionary structure in the Berea 
sandstone at this locality and there is obviously a 
line of disconformity between the Berea and Bedford 
TOPMATIONS 2. Cheyne se ei ey ae Fe ie eee en han 63+ 283 
1. Bedford shale—Soft, argillaceous, bluish-gray to 
gray shale on bank beneath the Berea sandstone. 
Farther down the run is chocolate, argillaceous shale 
which becomes mottled in color toward its mouth. 
The thickness varies. from 22 to 27 ft., depending 
upon whether it is measured to the lowest or highest 
point of the under surface of the Berea. Water 
leveltofiBigy Riu: SF, iG, Gahan ete ei rate an ee 22 22 
An earlier account of this section was published in the American 
Geologist,* together with a halftone of the western bank on which 
1 XXXIV (December, 1904), 344, 345. 
