CHAPTER XXXVII. 



REPORT ON THE GEOLOGY OF DELAWARE COUNTY. 



BY S. H. WINCIIELL. 



SITUATION AND AREA. 



Delaware county embraces the geographical center of the State. It 

 lies immediately south of Marion and Morrow, and north of Franklin, 

 which contains Columbus, the State capital. On the east it joins Knox 

 and Licking, and on the west Union. Its area, officially stated at 283,289 

 acres, embraces 81,975 acres of arable land, 104,(549 acres of meadow or 

 pasture land, and 96,665 acres of uncultivated or woodland. Its average 

 value per acre, exclusive of buildings, is $33.44, that of Franklin county 

 being $57.42, and of Hamilton, which contains the city of Cincinnati, 

 $84.39. 



NATURAL DRAINAGE. 



The Scioto and Olentangy Rivers cross the central portion of the 

 county from north to south. These streams, with their tributaries, con- 

 stitute the drainage system of the county. The Scioto is the larger 

 stream. They are both subject to sudden and very great increase of vol- 

 ume in freshet time. They afford many excellent water-power privi- 

 leges, some of which have been improved by the erection of mills for 

 flouring and manufacturing. As they are inclosed, throughout most of 

 the county, by high banks that are often rocky, they may be dammed 

 with ease and security to adjoining lands. 



SURFACE FEATURES. 



The eastern portion of the county is rolling, particularly the sand- 

 stone districts. This is due partly to the original unequal deposit of the 

 Drift, and partly to the effect of streams which have dug their channels 

 through it, and into the rock, in some instances, to the depth of fifteen 

 or twenty feet. 



The area of the shale and black slate was at first generally flat, but 

 the streams and all little ravines have so roughened the surface that it 

 should now be called rolling, or undulating, although there are yet many 

 wide flat tracts. The belt underlain by the shale and black slate is sep- 

 arated from the limestone belt by the valley of the Olentangy, which, 



