106 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



valley to a level as high as low cols in the district north of it, thus making 

 it possible for a stream to take a new course without having to open a 

 channel. Not only the Kanawha but Hurricane Creek and Guyandot River 

 (tributaries entering Teays Valley from the south) continue into channels 

 north of that valley. The channel into which the Kanawha and Hurricane 

 Creek were turned had gradation plains slightly higher than the rock floor 

 of Teays Valley, measurements with Locke level showing the height of the 

 gradation plain on the lower end of the present Kanawha, near the mouth 

 of Hurricane Creek, to be 680 feet above tide, but as these channels had 

 not become so filled with silt as Teays Valley, the drainage could pass into 

 them. It is this fact of a lower line of escape that seems chiefly responsible 

 for the diversion from a direct to an indirect course. 



Between the west end of Teays Valley and the south end of the aban- 

 doned channel at Wheelersburg the old line of the Kanawha usually nearly 

 coincides with that of the present Ohio, and its rock floor stands 160 feet 

 above the present stream. There is, however, one deflection worthy of 

 mention. For a few miles below the point where the Ohio passes the West 

 Virginia and Kentucky line, the old Kanawha channel is separated from the 

 present Ohio Valley by a narrow range of low hills. This valley, with its 

 deposits of gravel, was noted by Lyon in an early report of the Kentucky 

 geological survey,-' and was described more fully by Andrews in a report of 

 the Ohio survey.- By both, the gravel deposits were erroneously referred 

 to the glacial drift. In this old channel the silt filling is bu+ little less than 

 in Teays Valley, the surface of the silt being 680 to 700 feet above tide, or 

 50 to 70 feet above the rock floor. The gravel which underlies the silt is a 

 thin deposit resting upon the rock floor. The accompanying map (PL VII), 

 which embraces a portion of the Ironton quadrangle, shows a part of this 

 old valley and the present Ohio, with a range of hills between them. The 

 hills occupy the interval between the mouths of White Oak Creek and Pond 

 Run. Although they rise in places to a height of more than ] 00 feet above 

 the silt filling in the old valley, they are interrupted by notches so low that 

 small streams drain from the old valley through them to the present Ohio. 

 It is probable that the Ohio took advantage of similar low gaps in changing 

 from the old course to the present one. 



1 Sidney Lyon: Second Geoi. Eept. of Kentucky, 1856 and 1857, p. 360. 

 ^E. B. Andrews: Geology of Ohio, Vol. II, 1874, p. 441. 



