CHAPTER LXVII. 



REPORT ON THE GEOLOGY OF KNOX COUNTY. 



BY M. C. READ. 



LOCATION AND TOPOGRAPHY. 



Knox county, situated directly, south of Richland, is a continuation of 

 the southern elope of the table land which separates the waters of Lake 

 Erie froni those of the Ohio River. Its surface presents a succession of 

 hills, in part rugged and steep where influenced by the Coal Measure 

 rocks and the Waverly Conglomerate; in part symmetrically rounded, 

 and of very graceful outlines, where composed of the olive shales of the 

 Waverly. These hills are all intersected by narrow ravines in which 

 flow the tributaries of the larger streams, the latter uniformly occupying 

 ancient valleys of erosion, and bordered by rich alluvial plains. This 

 ancient river system of the county is very accurately defined. The 

 main channel, commencing in the north-west corner of the county, is 

 occupied by the head waters of Owl Creek, and is everywhere filled with 

 coarse water-washed gravel capped with a thick deposit of alluvial soil 

 The stream follows the line of this old channel, occasionally cutting 

 through headlands which formerly projected into it. At Frederick, for 

 a short distance it has a rock bottom, where a spur of the hills, extend- 

 ing out from the east side, is crossed by it, the old channel being easily 

 traced a little to the west. An exposure of the rock here shows that it 

 is much harder and more massive than usual, and had greater power of 

 resisting erosion. 



After the valley was filled up by the Drift, the modern stream found a 

 shorter course across this space, and has cut its recent channel through 

 the rock. This old channel extends to Mt. Vernon, where it divides, one' 

 branch continuing southward, and the other turning almost directly 

 east, affording a fine illustration of the manner in which the topography 

 of the country, before the Drift epoch, has controlled the course of mod- 

 ern streams, and in many places the location of our railroads. The 

 engineers of the Valley Railway, running northward from Cleveland, 

 have traced out such an old pre-glacial valley, and cross the divide in 

 the swamp that marks its highest elevation in the north-eastern part of 



