CHAPTER LXX. 
REPORT ON THE GEOLOGY OF WARREN COUNTY. 
BY EDWARD ORTON, ASSISTANT GEOLOGIST. 
Warren county is bounded on the north by Montgomery and Greene, 
on the east by Clermont, on the south by Clermont and Hamilton, and 
on the west by Butler. The Little Miami River, which crosses it diag- 
_ onally in a south-westerly direction, divides it into two nearly equal di- 
visions. Its western side slopes towards the valley of the Great Miami, 
and reaches this valley in its north-western corner. 
From these statements, it can be readily understood that the surface 
of the county consists of two main divisions of the tahle-land that con- 
stitutes south-western Ohio-—one of them lying between the two rivers, 
and forming a water-shed—the other making the beginning of the flat- 
lying tract that stretches away to the east and south, which has been 
noticed in previous reports. 
Tbe northern range of townships is traversed by the deep and com- 
paratively narrow gorge of Clear Creek, the east and west direction of 
which is unusual in the tributaries of the Miami. 
Turtle Creek and Union townships turnish striking examples of the 
waste that the country has suffered from erosion of an earlier day. A 
broad channel, at present occupied by Muddy Creek and Dick’s Creck, 
connects the valleys of the two Miamis through this district. The old 
branch of the Miami Valley Canal, from Lebanon to Middletown, followed 
this ancient channel, connecting the two points named above, without 
intermediate lockage. It is certain that by means of this channel the 
two rivers were formerly united, at least there are no rocky barriers to 
divide them, either the Little Miami holding the westerly direction, 
_ which it now has, from Morrow to Deerfield, or, as is more probable, the 
valley of the Great Miami being opened out by glacial erosion to the 
- south-east, the direction, indeed, in which glacial action has been most 
conspicuously exerted in south-western Ohio. 
_ The main valley of Turtle Creek furnishes another example of erosion 
which the present conditions do not fully account for. The stream no 
where runs upon a rocky bed, and to the north-eastward it furnishes an 
almost, if not quite, uninterrupted channel from the valley of the Little 
