ROSS COUNTY. . 653 
westernmost extension of this series of hills on the east side of the river, 
and bowlders are found half way up its northern slope. 
The country north of this boundary has suffered a much greater abra- 
sion and waste than that which lies south of it, and it is fair to refer the 
difference in this respect to the great difference in the later geological 
history of the two sections respectively. It certainly could not be with- 
out result that a slowly moving mountain of ice should advance over the 
face of a country composed of soft sandstones and softer shales. 
A new valley of Paint Creek, lying a few miles to the west of Chilli- 
cothe, has been once or twice alluded to in the course of the preceding 
pages. The origin of this new valley is unmistakably connected with 
the Drift history of the county, and it is:proper to treat of it at more 
length under this head. | 
The chief topographical features of the State, as is well known, are to 
; be referred to periods long antecedent to the Drift. There is the best of 
reason for believing that Ohio was raised above the seas many millions 
of years ago. Durmng all of the interval that has passed, it has been 
slowly acquiring its surface relief, under the atmospheric agencies to 
which it has been subjected. Cases are, however, sometimes met in 
which the old channels of drainage were so blocked by accumulations of 
drift, that the streams, on resuming their course after the height of the 
Glacial period had passed, found it easier to work out new channels than 
to clear the old ones. These new valleys agree in being narrow, in being 
shut in with precipitous walls of rock, and in being free from Drift de- 
posits. Several instances of this sort have been given in the reports of 
the Survey, but the present case is by far the most striking yet found in 
the Third Geological District. 
The Hillsborough and Chillicothe turnpike, which enters the county at 
the south-western corner, extends through the broad and fruitful valley 
of Paint Creek, which here has a north-easterly direction. The valley 
is perfectly defined by ranges of hills, about five hundred feet in height, 
on either side. The northern wall is broken for the passage of several 
tributaries, as Buckskin Creek, Upper and Lower Twin Creeks, etc., but 
the continuous outline of the southern wall is scarcely interrupted. The 
turnpike crosses the creek three miles below Bainbridge, and thencefor- 
ward for ten miles the stream is never out of sight upon the right hand. 
All at once, however, and as if by magic, it has disappeared. The turn- 
pike still holds the valley, the boundaries of which are just as distinct 
as before. There is certainly no conspicuous notch in the southern wall 
through which one could guess that a stream of such volume could have 
found its way. By following the stream, however, instead of the valley, 
