WABASH DRAINAGE SYSTEM. 193 



known as Mill Creek, is about 40 miles in length, and its west fork, known 

 as Walnut Creek, fully 50 miles. Below the junction of these forks the 

 stream has a leng-th of about 45 miles, if the minor windings of the channel 

 are disregarded. 



BAST WHITE RIVEE. 



This large ti'ibutary enters the West or main White River about 40 

 miles above its mouth. It drains the district immediately east of that 

 di-ained by the main river and has an area nearly as great, there being 

 about one-sixth of the State of Indiana tributary to it. 



The headwater portion above Columbus, Ind., is usually known by 

 the name of Blue River, the name East White being applied to the stream 

 below its junction with Flat Rock Creek at that city. The name Driftwood 

 is also applied to the lower portion of the river. Inasmuch as there is 

 another stream within the State called Blue River, it is unfortunate that this 

 name is applied to the headwater portion of East White River. 



The upper half of the drainage basin of East White River lies within 

 the g'laciated districts of eastern and southeastern Indiana. The streams 

 find their sources in the elevated Upper Silurian limestone belt, in the 

 eastern part of the State, and descend rapidly westward to the Devonian 

 shale area. The main stream leads through the western part of the drainage 

 basin, and hence receives nearly all its tributaries from the east. The 

 drainage system is, therefore, very unsymmetrical. 



Although these headwater tributaries make a gi'eat descent in passing 

 down to the basin of Devonian shale, they have carved very insignificant 

 channels. The valleys are usually so shallow that their bridges may be 

 seen for miles back from the borders of the streams. A portion of the 

 Muscatatuck drainage system is, however, characterized by deeper channels, 

 a feature which is probably attributable to the greater age of that system. 

 It lies outside the limits of the newer, or Wisconsin, drift, while the principal 

 tributaries of the East White farther north flow throughout most of their 

 course within the limits of the newer drift sheet. 



The northern tributaries, Blue River and Flat Rock Creek, have their 

 sources in northeastern Henry County at an elevation of about 1,100 feet 

 above tide. They make a descent of about 500 feet in the 100 miles from 

 their source to the junction at Columbus, or an average fall of about 5 feet 

 per mile. In the lower 35 miles of its course, from Shelbyville to Columbus, 



MON XLI 13 



