420 
and below. The valley is wide in Morgan County because of the easily 
eroded Knobstone sandstones and shales, through which the valley has 
been cut. It is wide in Greene County again on account of the same funda- 
mental reason. Here the valley is in the soft sandstones and shales of the 
Chester Group and the Coal Measures. In this county, however, the 
Illinois glacier undoubtedly was an important factor in widening the 
valley. In Owen County the strata in which the “Narrows” occur, are 
hard, resisting limestones, which are little disintegrated by weathering 
and suffer even less by abrasions. The widening of the valley in this 
region must be carried on mainly by solution, which is a much slower proc- 
ess than those involved in the region above and below. This narrowing 
of the valley is identical with the appearance of the limestone bluffs in the 
vicinity of Gosport. The same condition is to be seen on the Hast Fork of 
the White River, where the yalley is exceedingly wide in the Knobstone 
region, and becomes almost gorge-like in the limestone region. 
Furthermore, if the valley in the limestone region were post-glacial 
there would be very little alluvium below the present channel. This is not 
the case. Wells at Spencer prove that the alluvium is at least 100 feet 
deep, just as it is in the wide regions of the valley. 
White River Valley, then, in its passage across the limestone region of 
Owen County is not a new opening. It is the same valley that is seen in 
the wide portions of both Morgan and Greene counties. It is the same 
valley that has carried the waters of the basin above since the time that 
the present fundamental topographic features were initiated. In fact this 
part of the valley and channel is more nearly where it has always been 
than any part either above or below, for the simple reason that at this 
point the Illinois glacier but little more than crossed the valley, while 
both above and below, it crossed for many miles farther, and deranged the 
drainage accordingly. 
We are now ready for the final chapter of the history of the Flatwoods 
region, the chapter which really gives the explanation of the Flatwoods 
phenomena. 
THE GLACIAL HISTORY OF FLATWOODS. 
It is not the writer’s purpose to give here a treatise on glaciers and 
glaciation, nor to give an intricate and detailed history of the period of 
glaciation known to have been present in the Flatwoods region. The pur- 
pose here rather is to show the relations of the edge of the Illinois ice- 
