CHAPTER LXXIX. 
RHPORT OF THE GEOLOGY OF DARKE COUNTY. 
BY A. ©. LINDEMUTH. 
I. SITUATION, AREA, ETC. 
Darke county lies in the extreme western part of the State, a little 
south of the centre, adjoining Indiana on the west, bounded by Mercer 
county on the north, by Preble on the south, and on the east by Shelby 
and Miami. It is nearly rectangular in form, and embraces an area of 
376,390 acres; 208,782 of which are cultivated land, and the remaining 
172,608 acres are uncultivated or woodland. 
ss ‘ 
II. TOPOGRAPHY. 
Geologically speaking, this county is situated upon the western termi- 
nus of the great divide, lying rather upon its southern slope; hence is 
properly reckoned, both as to its physical and political position, as belong- 
ing to Southern Ohio. The summit ridge enters the county in the north- 
eastern. part, bearing south-west through the northern part of Patterson 
township, through the southern parts of Wabash and Allen, and passing 
- out near the middle of Jackson township. This, at once, affords an idea 
of the general topography of the county as regards the dip of the land 
and the configurations due to water agencies; to which might also be 
added much other information derivable by analogy from similarly situ- 
‘ated counties, of the contour or surface features due to other erosive and 
accumulative agents. 
The numerous springs which occur along this water-shed, as well as 
the surface streams, would naturally give rise to many avenues of drain- 
age; but, owing to the proximity of their origin, could certainly not at- 
tain to any considerable magnitude within the limits of the county. The 
natural system of drainage, nevertheless, is by no means an imperfect 
ene. Greenville Creek, the largest of the streams, takes its rise in the 
northern water-shed, a little without the county. Following the general 
slope of the country, it flows south-east in an almost uninterrupted course, 
until coming in contact with the large kame upon which Greenville is 
situated, flows around it in a north-easterly direction, and then, with 
