CHAPTER XXXIX. 
RHPORT ON THE GEOLOGY OF UNION COUNTY. 
BY N. H. WINCHELL. 
SITUATION AND AREA. 
Union county lies next west of Delaware, which is the most central 
county in the State. It embraces 272,318 acres, of which 72,770 are arable 
or plow land, 67,670 meadow or pasture land, and 131,873 uncultivated or 
woodland (see “‘abstract of the valuation of taxable real estate of Ohio,” 
in the the year 1870, by the Auditor of State, James H. Godman.) 
NATURAL DRAINAGKH. 
The surface drainage all passes into the Scioto valley, by streams 
which flow with gentle current in a south-easte ly direction. They rise 
in the Logan county Corniferous area, a region of very rough or hilly 
surface, rising several hundred feet above the surrounding Waterlime 
flats, and toward the south-east enter upon another area of Corniferous, 
which, although presenting different sur‘ace features, yet 1s not so broken 
as the Logan county area. 
There is a remarkable uniformity in direction and alternation in these 
streams. The principal valleys have a slope to the east or south-east, 
toward the Scioto, the valley of which is excavated over a hundred feet 
in the bed rock, in Delaware county. To one who has closely observed 
the systems of drainage in the various counties, and has aimed to ascer- 
tain, from the effects seen, the causes that located streams in various 
parts of north-western Ohio, this alone suggests the halting retreat of a 
glacier across the county, throwing down greater accumulations of Drift, 
where it remained stationary for a length of time. Such would be the 
divides between the streams, the valleys being in those belts where the 
Drift was left thinner. But, with a single exception, nothing of this is 
indicated by the surface features, se far as the time devoted to the survey 
would disclose. The whole county was very carefully examined. In 
counties further north-west, where such moraines are seen to guide the 
drainage diagonally across the general slope of the surface, the tributary 
