DRAINAGE OF SOUTHERN INDIANA. 
INTRODUCTION. 
Area to be discussed. — Only those features of the drainage of 
southern Indiana which are dependent upon geological structure 
and are not controlled primarily by glacial drift will be dis- 
cussed. This limits the discussion to that portion of the state 
that lies south of a line running from Indianapolis east to the 
Ohio state line, and from Indianapolis southwestward along the 
course of West White River to the mouth of that stream. 
While the eastern tributaries of the West White River from 
Indianapolis to the mouth of Bean Blossom Creek, and the tribu- 
taries of East White River in northern Shelby and Johnson coun- 
ties, owe their positions largely or entirely to the drift,’ the main 
streams of the area referred to are controlled by the underlying 
Strata. 
The driftless and adrift-covered regions.—The driftless region of 
southern Indiana is an irregularly triangular area, with the base of 
the triangle along the Ohio river, reaching from Mount Vernon 
to a point a few miles above Jeffersonville, a direct distance of 
135 miles, and the apex of the triangle near the northeast corner 
of Monroe county, 135 miles northeast of Mount Vernon and 85 
miles slightly west of north from Jeffersonville. All other por- 
tions of the area under discussion are, or have been, more or less 
covered by the drift. 
Over most of the region both directly east and directly west 
from the unglaciated area the covering of drift is comparatively 
thin. Inthe region to the east especially, the drift covering is 
rarely as much as 100 feet thick, and many of the streams have 
cut down through it and into the underlying rocks. In some 
cases these streams occupy preglacial channels; in others the 
tThese small streams are not included in the following remarks regarding the 
drainage. Neither are the streams between West White and Wabash rivers discussed, 
although those streams are shown on the map, Plate VI. 
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