Wavcrlv Fortnations of Central Ohio. — Prosscr. 345 
northwest l)aiik, aiul porliaps 6^^ feet is near 
the thickness of tlie main part. The base of 
the sandstone on this bank is not a uniform 
hne and the underlying shale to the level of 
the run varies in thickness from 6 to 9 feet. 
This character is shown in Fig. 6. The weath- 
ered ledge is much stained, rusty to brown- 
ish in color and the upper part contains much 
marcasite as is generally the case in the various 
sections reported. 
I. Bedford shale. Bluish-gray to gray in color, 22' 22' 
on the bank beneath the Berea sandstone ; but 
down the run are mottled and reddish shales 
before reaching Big run. 
On the western bank of Big run above the mouth of 
Smith run and the house of Mrs. Nancy Cole is a ledge of the 
Berea sandstone, ahhough it is not so well shown as in the 
two glens just described. Drift and boulder clay fill the val- 
ley of Big run above the ledge of Berea sandstone, so that the 
Sunbury shale is not shown. 
Along the stream about one mile southwest of Big run and 
parallel with it, exposures of Ohio shale commence where the 
stream and highway cross the Franklin-Pickaway county line 
one and one-half miles west of the Fairfield county line. 
The shales are uniformly black, even, highly fissile and weath- 
er brownish. They are exposed almost continuously for 
one-half mile up the stream, although at no place rising more 
than about ten feet in the stream-banks, with a thickness of 
forty feet, according to barometric readings. One-half mile 
up the stream the Bedford shale appears, almost in contact with 
the Ohio shak, and where it first appears there is an exposure 
of fifteen feet, the lower part of which is bluishi, the middle 
portion mottled and the upper five feet dull red in color. The 
texture of the shale is typical, being gritless, much jointed and 
passing rapidly into small flakes or into a stiff clay. About two 
feet of Berea sandstone is shown near the head of the south 
fork of this run. 
Along the east and west road one mile south of the Frank- 
lin-Pickaway county line, at a point just one mile west of the 
Fairfield county line is another exposure of the Berea which at 
this locality is a brownish, coarse grained sandstone, two 
