CHAPTER XXXVII. 
RHPORT ON THE GEOLOGY OF DELAWARE COUNTY. 
BY N. H. WINCHELM, 
SITUATION AND ARFA. 
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, 104,649 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, 
