178 J. F. NEWSOM 
are practically the same at the present as they were in pregla- 
cial times. The Knobstone sandstones, with their capping of 
limestones, rise in an eastward-facing escarpment unbroken, 
except where cut through by East White River, from the Ohio 
River at the south side of Harrison county to the northeast 
corner of Brown county. This escarpment rises from 200 to 
400 feet above the lowlands of the central drainage basin imme- 
diately east of it, while to the west the country is rolling and 
descends gradually. The streams rising near the escarpment at 
the east flow down the gentle slope to the west and finally enter 
the Ohio, White, or Wabash rivers. 
The control of the structure upon the drainage lines of this 
area is best seen immediately west of the Knobstone escarp- 
ment between the East White and the Ohio rivers (Plate VI). 
North of East White River apparently only the general course 
of the drainage is controlled by the structure; while in a 
general way the longest tributaries of the streams are those 
coming in from the east and northeast, this feature is by no 
means clearly marked, even in the area underlain by the com- 
paratively hard Lower Carboniferous limestones and Mansfield 
sandstone. 
It is noticeable that the streams of the western area which 
flow across both the area underlain by the Lower Carboniferous 
limestones and that underlain by the sandstones at the base of 
the Coal-measure (Mansfield sandstone) are not deflected as 
they pass from the limestone into the sandstone area. 
The Mansfield sandstone is often massive and forms a rugged 
topography in the region in which it outcrops, and it might be 
expected that the streams would be deflected to the north or 
south by it. However, no such change in the stream courses is 
to be seen; instead of being deflected they pass directly from 
the limestone area across the sandstones, through which they 
have cut deep valleys, until they reach the comparatively flat 
region underlain by the soft Coal-measures shales at the west 
side of the Mansfield sandstone. 
These conditions lead to the conclusion that the streams 
