374 THE ICE AGE IF NORTH AMERICA. 



It is evident that, while the ice-front rested over the 

 northwestern portion of Pike county, and was depositing the 

 terminal moraine just described, there ought to have been, 

 during the whole time, a strong current of glacial drainage 

 rushing down through Baker's Fork into Brush Creek, de- 

 positing more or less of overwash gravel along its bed. But 

 there are no marks of such a line of glacial drainage here. 

 There are no terraces on Baker's Fork ; and no granitic peb- 

 bles are to be found in its valley, where they ought to exist 

 in great numbers if there had been a glacial torrent pouring 

 into it from the terminal moraine. The uniformity with 

 which these lines of glacial drainage are marked by terraces, 

 and by the presence of northern pebbles gathered from the 

 glaciated region, is, as we have already seen, one of the most 

 striking features just outside the glaciated region all the way 

 from the Atlantic Ocean to the Mississippi River. For the 

 exception in the present instance there would seem to be but 

 one explanation, and that is as complete as it is unexpected. 

 The ice-dam in the Ohio River, supposed on other evidence 

 to have been in existence for a short time at the climax of 

 the Glacial period, perfectly accounts for this exceptional 

 phenomenon, while no other adequate cause whose existence 

 is at all probable can be found. The explanation is as fol- 

 lows : 



The height above the tide of this moraine, which closes 

 up the opening between Paint and Brush Creeks, is between 

 nine hundred and a thousand feet, corresponding very closely 

 with the supposed height of the water-level produced by the 

 ice-dam at Cincinnati. Hence, during the existence of the 

 dam, there would have been no chance for the formation of 

 a glacial torrent down Brush Creek, since back-water extended 

 to the very ice-front at its head, and the terminal deposit was 

 laid down in still water. The limitations of this deposit at 

 the head of Baker's Fork and the level surface of Beech 

 Flats, therefore, furnish a complete verification of the theory, 

 and prove beyond question the reality of the Cincinnati dam. 



Furthermore, the lower portion of Paint Creek is so situ- 



