DRAINAGE OF SOUTHERN INDIANA 175 
stone strata, the overlying Lower Carboniferous limestones and 
the Mansfield sandstone. This valley varies in depth from less 
than fifty to over two hundred and fifty feet ; its length is about 
seventy-five miles. In width the bottom of the valley (which 
is filled with alluvium from fifty to seventy-five feet or more), 
varies from one-half mile to over one mile. 
Thus it is seen that instead of carving out a valley along the 
strike of easily eroded strata, southward from Rockford directly 
to the Ohio, a distance of fifty miles, East White River turns to 
the west, flows through a valley cut across hard strata, and 
finally reaches the Ohio through the Wabash at a point over 
150 miles from Rockford. 
Two hypotheses may be advanced in explanation of the 
course of East White River below Rockford. 
The first is that the present is approximately the original 
course of the river; that as this region was first elevated the 
drainage from the land at the east was deflected to the south 
parallel with the Knobstone sandstones and behind (z. ¢., east of 
them), or else that it shifted itself to this position during 
its early history; that in the vicinity of the present village of 
Rockford the drainage turned to the west, cutting across the 
edges of the strata, and that it deepened its valley in this posi- 
tion as the strata were elevated—gradually establishing itself 
in approximately the position now occupied across the Knob- 
stone, the Lower Carboniferous limestone, and the Mansfield 
sandstone. Even though this entire region may have been 
approximately baseleveled since the orginal drainage was estab- 
lished, elevation subsequent to the baseleveling would have 
re-established the main drainage along its original lines. 
The width of the valley throughout its length from the Mus- 
catatuck to the Coal-measures suggests an age greater than has 
elapsed since the ice invasion, and makes the above explanation 
seem probable. The present course of the stream through its 
gorge below the mouth of the Muscatatuck cannot be explained 
by stream capture, if it be supposed that East White River origi- 
nally entered the Ohio in the neighborhood of New Albany. — If 
