BOSS 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. During 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, 



