394. GEOLOGY OF OHIO. 
could be approximately described as the portions of the county that 
have an elevation of not more than 250 feet above the Ohio River. 
On the other hand, the uplands embrace the lands above this level. A 
large proportion of them, however, lie at an elevation between 400 and 
600 feet above the Ohio. This division of the surface of the county is 
much less definite on the east side of the river than it is on the west, 
for the reason that the Drift deposits are heavier in the first named 
district. In other words, the lines of the valleys are here harder to be 
traced. There are areas of unmistakable uplands, but they are con- 
nected with the valleys by slopes of considerable extent, which com- 
pletely obscure the true outlines of the rocky floor. 
The uplands proper are remnants of the Blue Limestone plateau that 
once occupied all of south-western Ohio, but so much of which has 
already been removed by aqueous and glacial denudation. They are 
almost universally covered with shallow deposits of drift, but over very — 
large areas the character of the underlying rock shows through, giving 
its peculiar features to the topography, to the agricultural capacity, and 
to the water-supply of the districts occupied. These upland drift de- 
posits are in considerable part derived from the waste of blue limestone 
land to the northward, so that a closer bond of connection exists between 
the soil and the underlying rock than is usually found in drift-covered 
regions. A more detailed description of the drift deposits of the county 
can appropriately find place here. 
DRIFT BEDS. 
The divisions of the drift that have been recognized in those portions 
of the Third Geological District already reported upon, are found here 
also. The lowest of these deposits, or that which rests directly upon the 
bedded rocks, is the bowlder clay. 
1. This formation is shown with great distinctness and in very numer- 
ous exposures in Butler county. Almost every stream in some portion 
of its course discloses it. Its general composition has been fully enough 
described in previous reports. A particular feature of the bowlder clay 
in Butler county is that of ancient vegetable growths, branches, trunks 
and roots of trees in large quantities. @xamples can be seen in follow- 
ing almost any stream to its source, but one or two points may be named 
which are specially noteworthy in this respect. Collins’ Run, near Ox- 
ford, a small tributary of Four Mile Creek, shows in its banks very 
numerous exposures of these pre-glacial and inter-glacial forest growths. 
