174 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



through a narrow rock-bound valley to enter Brushy Fork. The stream 

 then follows the valley of this small tributary to its former head, 3 or 4 

 miles south of the county line. It then crosses an old divide into the 

 valley of a larger stream coming in from near Mabees that discharged 

 southwestward into the old Kanawha. It follows this valley down to the 

 junction with Rock}^ Fork near Wallace Mills. The old valley of this 

 tributary probably discharged westward from Wallace Mills to the old 

 Kanawha along Rocky Fork (reversed), though possibly it continued down 

 the line of the present stream and entered the old Kanawha channel near 

 Harrison Mills. The distance to the old channel of the Kanawha, by either 

 route, is only two miles from Wallace Mills. From Harrison Mills the Little 

 Scioto River occupies the old channel nearly to the present Ohio. It, how- 

 ever, cuts off a rock point west of the old channel, just before entering the 

 present Ohio. 



Rocky Fork rises in the uplands west of the old Kanawha channel in 

 southeastern Pike Countj', and follows that channel southward for several 

 miles before turning east to join Brushy Fork. In leaving the old channel 

 it seems to have disregarded the most favorable line of discharge. 



The only cause for these incursions of the present drainage into the 

 hills which has suggested itself to the writer is found in the large amount of 

 filling which the old channel received, there being in places a depth of 60 

 feet of silt on the old rock floor. This amount of filling was pei'haps suffi- 

 cient to raise the drainage lines above the Ifevel of low divides among 

 neighboring hills to the east and thus bring about the singular system of 

 drainage presented by the Little Scioto and its tributaries. It is, however, 

 somewhat doubtful if this silt filling caused all the changes, and they may 

 prove to be independent of it. 



SCIOTO RIVER. 



The Scioto is the chief drainage system of central and southern Ohio, 

 The main stream has a length of about 210 miles, and with its tributaries 

 drains an area of 6,400 square miles. Its source is in eastern Auglaize 

 County, and its mouth at Portsmouth, Ohio. 



The region drained by the Scioto and its tributaries has undergone a 

 series of changes of peculiar interest, some of which have been outlined in 

 the discussion of the Ohio and Muskingum drainage basins. The present 



