70 



THE PREGLACIAL DRAINAGE OF OHIO. 



ity of Carthage. A short ravine joined them, from the hills 

 where the Little Miami discharges, but that river was not then in 

 existence, being a post-glacial stream. 



It will be perceived that when old Limestone turned north- 

 ward, it was separated from the Licking only by the col at (B). 

 Between this col and the one at Sedamsville (C) the Licking 

 flowed north into Mill creek valley where it continued its north- 

 erly course. Receiving old Limestone at (G) it passed on and 

 entered the valley of the Great Miami at Hamilton. 



From the west side of the col at (C) a ravine extended to 

 North Bend. The hill behind this village, though apparently 

 continuous with the blue limestone formations on either side, 

 is composed of glacial material. This fact was first disclosed 

 when the railroad which passes through here undertook to make 

 a tunnel ; it was found that the limestone was absent. Conse- 

 quently only a cut was needed. This cut is in the lowest part of 

 the deposit; the higher hills to the eastward are also composed 

 of drift. This proves that the ravine from (C) formerly turned 

 to the north at this point, reached the Great Miami valley at 

 Cleves, and there turned west along the present course of the 

 river. 



The wide valley below the col (D) has an interesting his- 

 tory. It is continuous from Hamilton to the mouth of the Ken- 

 tucky river. This fact, in connection with the rapid narrowing 

 of the Ohio between Carrolton and Madison, together with the 

 certain evidence of a col at the latter place, proves beyond 

 question that this ancient bed was eroded by the Kentucky 

 river. In other words, that stream, instead of following the 

 present Ohio as it does now, or flowing across Indiana, turned 

 to the east and north .to join the Licking at Hamilton. There 

 is no other channel through which it could have gone. The 

 hills in every other direction, except at the gorge below Madison, 

 are unbroken. From Lawrenceburg it extended almost due north 

 through the valley now partially occupied by the Whitewater 

 and Dry Run, to the point (H). Here it turned east, and at (I) 

 reached the Great Miami, following that valley to Hamilton. 

 From Hamilton northward the old river bed is filled with drift 

 and has not been traced. There can be no doubt, however, 



