\ BEDFORD AND BEREA FORMATIONS IN CENTRAL OHIO 603 
northern bank as followed down stream, with the consequent 
decrease in thickness of the upper part of the Bedford. 
On the northern bank, 6 ft. farther down stream than the angle 
shown in Fig. 4, the Berea has thickened from 133 in. to 2 ft. and 
its base is stratigraphically lower than in the angle of the fall and 
cuts off some of the upper part of the Bedford. This is clearly 
shown by some of the thin sandstone layers, about } in. thick, 
in the very upper part of the Bedford at the angle of the fall, 
which are cut off by the base of the Berea as it is followed down 
stream. Fifteen feet farther down stream from the point where 
the Berea is 2 ft. thick, it has increased in thickness to 2 ft. 4 in. 
Twenty feet farther down the run, nearly under the tree, the Berea 
has decreased from 2 ft. 4 in. to 15 in., and the upper part of the 
Bedford increased accordingly. This bank is shown in Fig. 5 
where the hammer marks the contact of the Sunbury shale and 
Berea sandstone, below which the upper part of the Bedford 
shale is shown. At the fence 70 ft. farther down the stream 
and still on the same side, the Berea has thickened to about 
5 ft. It again thins as followed down stream and 20 ft. below the 
fence at the lower end of the cliff it is only about 1 ft. 8 in. thick. 
In all this interval the upper surface of the Berea remains about 
uniform and the differences in thickness are due entirely to changes 
in its basal portion. The following section was measured at the 
lower end of the cliff farthest down stream: 
SECTION OF LOWEST CLIFF ON SLATE RUN 
Total 
No. Thickness Thickness 
Feet, Inches Feet, Inches 
4. Berea sandstone.—Composition similar to that in the 
other sections at this locality. It is only about 1 ft. 
8 in. thick, but thickens rapidly as followed up 
stream. The lower surface is irregular and rough, 
corresponding to inequalities in the upper surface of 
the Bedford formation. No indication of concre- 
tionary structure. Conspicuous line of discon- 
formity between the Berea and Bedford formations 1 8 S38 
3. Bedford formation.—Bluish, argillaceous shale with 
occasional thin, arenaceous layers which a short 
distance farther up the bank are cut off by the 
descending base of the Berea sandstone.......... On ir AG 
