184 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



old Wabash system. The size of the valley mdicates that it drained at 

 most only a few counties of western Ohio. The old drainage of a considei-- 

 able pai-t of the region now drained by the Great Miami appears to have been 

 independent of this line. It is probable that the old drainage south from 

 the latitude of Dayton followed nearly the course of the present lines to the 

 Ohio. As already indicated, the old Ohio was entered by the Oreat Miami 

 near Hamilton. The latter stream makes slight departures from the line of 

 the old Ohio below Hamilton, the old Ohio channel being in part farther 

 west than the Grreat Miami. 



WHITEWATER RIVER. 

 OUTLINE OF THE PRESENT SYSTEM. 



Several streams which have their sources in a moraine in southern 

 Randolph County, Ind., and southwestern Darke County, Ohio, converge 

 southward to form the Whitewater River. These are known as West Fork, 

 Martindale Fork, Greens Fork, Nolands Fork, and East Fork. The first 

 four become united between Cambridge and Coimersville to form the West 

 Whitewater; the fiftli (East Fork) unites with the West Whitewater at 

 Brookville. The area of the entire Whitewater drainage basin is about 

 1,500 square miles. 



The headwater portions for 1.5 to 20 miles are flowing in channels cut 

 in the drift. The East Fork then, near Richmond, enters the rock, and has 

 carved its course partly in rock from that point to Brookville. The West 

 Fork encounters rock at only a few points. Below Coimersville it is in a 

 partially filled preglacial valley, with broad bottom and elevated uplands 

 on either side. 



The West Fork, with its headwaters, constituted an important line of 

 drainage for the waters from the ice sheet at the time the moraine above 

 referred to was forming, and probably also at earlier stages in the Glacial 

 epoch. It is in consequence a gravel-filled valley, and the work of the 

 present stream has been merely a removal of a small portion of these gravel 

 deposits. Above Cambridge it has cut scarcely 20 feet into these deposits. 

 The depth gradually increases southward to Brookville. At Brookville and 

 below that city it has formed a channel 60 to 75 feet in depth. The surface 

 of the gravel deposits in the headwater portion above Cambridge has a 

 southward descent of nearly 10 feet per mile. From Cambridge to the 



