MIDDLE OHIO DRAINAGE SYSTEM. 105 



that of the present Ohio. The removal of the col near Manchester, at 

 the head of the southwestern tributary, probably represents but a smalL 

 part of the work accomplished, for the channel of this tributary seems to 

 have been enlarged throughout its length of fully 50 miles. There was 

 apparently, also, some enlargement of the headwater portion of the old 

 west-flowing stream beyond the divide., for the Ohio River bluffs are excep- 

 tionally abrupt for a few miles west from Manchester. 



The change to the present course from Wheelersburg to Portsmouth 

 seems to have required but little work. The principal cutting appears to 

 have been in the 3 or 4 miles between Wheelersburg and the mouth of 

 Tygarts Creek, a north-flowing stream which reaches the Ohio just above 

 Portsmouth and which apparently connected there with the stream above 

 noted that' came in from the southwest. The ridge crossed east of Ports- 

 mouth is prominent on each side of the Ohio, its altitude being about 300 

 feet above the old Kanawha channel. But the space ribove the bluffs is 

 about 1^ miles, and this may have contained a sag or broken-down part of 

 the ridge, so that the cutting need not have been so much as the height 

 of the present bluff would indicate. The maximum allowance for cutting 

 can not exceed 300 feet in depth, 1^ miles in width, and 3 miles in length, 

 and the proba,bilities are that the cutting was much less than that amount. 



The abandoned line of discharge for the Kanawha River between St. 

 Albans and Huntington, W. Va., known as Teays Valley,^ was brought to 

 notice some years ago by White- and discussed more fully later by Wright,^ 

 under the name of Teazes Valley. Tlie rock floor of this abandoned valley 

 stands 630 to 650 feet above tide, or 145 to 165 feet above the Ohio at 

 Huntington, W. Va., where it connects with that stream. Measurements 

 with Locke level show that the rock floor at the east end near St. Albans 

 has an altitude of 630 to 640 feet, while at the mouth of the Big Sandy 

 River, just below Huntington, the rock floor of its broad terrace has an 

 altitude of 630 feet. Between these places points were found where the 

 rock floor reaches 650 feet, but it is not certain that the lowest part of the 

 channel floor was exposed. The old gi-adation plain is now covered with a 

 thick deposit of silt, whose surface stands 700 to 720 feet' above tide, or 60 

 t(~> 80 feet above the rock floor. This silting was sufficient to build up the 



'Geologic Atlas U. S., folio 69, Huntington, W. Va. 

 '■'Appendix to AVright's Glacial Boundary in Ohio, 1884, p. 84. 

 ■'Bull. U. S. Geol. Survey No. 58, 1890, pp. 86-88. 



