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 exhibitiou of it. Dr. Hurst, of Wil- 

 liamsport, has sent me a sample of the slate, prepared for use as a writ- 

 ing blate. 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 

 Williamsport 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 i3 

 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- 



