590 GEOLOGY OF OHIO. > 
Madison townships, the eastern highlands project themselves westward 
in spurs, the Waverly will be found. The Waverly sandstone is seen in 
good development on the waters of Salt Creek, in Salt Creek township, 
in Hocking county. Should the proposed railroad to the coal fields in 
Vinton and Jackson counties pass down Salt Creek, through the Salt 
Creek townships of Pickaway and Hocking—a feasible route—valuable 
quarries of this stone might be opened. There would be little superficial 
drift to be removed. Directly west of the line of the Waverly is the 
great Ohio Black Slate of the former geologists, the Huron Shale of Dr. 
Newberry, which dips beneath the Waverly to the east. This slate un- 
derlies the larger part of the county, but is generally so buried by the 
Drift and other surface materials as to be seldom seen. It appears, how- 
ever, in the beds of Darby and Deer creeks. At Williamsport, in Deer 
Creek township, there is a good exhibition of it. Dr. Hurst, of Wil- 
liamsport, has sent me a sample of the slate, prepared for use as a writ- 
ing slate. If by some baking process it be rendered harder and tougher, 
and, consequently, more like the metamorphic slates of Vermont and 
Wales, this great deposit of slate might become of economic importance. 
There are many places in Ohio where it might be quarried at very slight 
cost. In the slate at Williamsport are sometimes found thin flakes of 
asphalt, or hardened bitumen, but not in sufficient quantity to be valu- 
able. The same substance is found in the black slate elsewhere. At 
Willlamsport we find small quantities of iron pyrites, or bi-sulphide of 
iron, imbedded in the slate. It is of no value, except for the manufac- 
ture of copperas, or sulphate of iron; and for this purpose, it does not 
exist in sufficient quantity. 
The Black Slate formation where measured in the Ohio River hills is 
a little over three hundred feet thick. It extends from the Ohio River 
to Lake Erie, and is one of the most distinct and noticeable features of 
our Ohio geology. The black color of this slate is derived from the large 
amount of bitumen it contains. Prof. Wormley, Chemist of the Geological 
Survey, reports the volatile matter (bitumen chiefly) as 8.40 to 10.20 per 
cent. This is nearly one-fourth as much as we find in some bituminous 
coals. We have, therefore, in the three hundred and twenty feet of 
black slate, bituminous matter enough to furnish with the requisite bitu- 
men a seam of coal from sixty to eighty feet thick. The conditions 
under which this formation was deposited involved comparatively quiet * 
water, charged with a constant supply of fine sediment, with which there 
was at all times commingled organic matter, which alone could have 
furnished the bitumen. The even distribution of the bitumen through- | 
out the entire mass of the sediments would imply that the water abound- 
