24 BULLETIN OF THE LABORATORIES 



lower end of this there are drift-hills whose summits are at least 150 

 feet above Walnut Creek which now flows between them and the hills 

 to the east. These deposits, extending for miles, and uniting with 

 those made by the huge eddy formed by Mount Logan (which forced 

 the glacial currents in the Scioto to the western hills), completely shut 

 off these two pre-glacial ravines, and forced the water coming through 

 the Maple Swamp gorge to skirt the hills, overflow the col back 

 of Rattlesnake Knob, and sever that peak entirely from the range of 

 which it formed a part. Through the narrow gorge thus made, Wal- 

 nut Creek finds its way, and reaches the river miles below. 



