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wells reveal a great trench filled with an irregular series of clays and 
water-bearing sands and gravels. This is the region of the driven wells 
(see map of “Driven Well Area”). In the hill region and most of the region 
in Pigeon Plain north of the terrace all wells strike rock at comparatively 
shallow depths. 
As the name would imply, in the region of driven wells all wells are 
driven. This method of sinking wells makes accurate well sections hard 
to obtain. The only thing that can be obtained accurately is the depth or 
depths of the water-bearing strata and in a general way something of 
what was passed through before water was found. Only a few open wells’ 
are found in this region, and they were dug so long ago that less can be 
learned from them than from the driven wells. 
The depth of the driven wells varies considerably, in one place a differ- 
ence of 10 feet having been noticed betwen two wells on level ground not 
40 feet apart. The deepest wells found are near Rockport. One is 70, the 
other 65 feet. Neither struck rock. The normal depth of wells in middle 
Lake Plain and Northern Pigeon Plain south of the terrace range from 17 
to 40 feet. Very few wells are deeper. One well, 56 feet deep, in the nar- 
rowest part of Lake Plain, did not strike rock. In River Plain they range 
from 30 to 60 feet. 
From these wells we learn something of the griginal depth of this filled 
valley. If all these sands and gravels, which underlie Lake, River and a 
portion of Pigeon Plain could be removed, a valley extending at least 56 
feet and probably more than 70 feet below the present plain level, and hay- 
ing its sides of middle carboniferous formation, would be revealed. (See 
Fig. 2.) 
This valley is the same depth as the half-filled Ohio gorge, of which it 
is a continuation. It is filled with the same materials. The hills on each 
side are covered with typical river bluff loess in the same manner as those 
on the erosion scarp of the Ohio. The levels of the Plains are so nearly 
the same that a portion of the waters of the flood of 1884 rushed through 
the Lake Plain, and entering Pigeon Plain, one part followed the terrace 
and then turned southward to meet the other part and join the waters of 
the Ohio again where Pigeon and River Plains meet. This stream was 
four feet deep, and flowed with such swiftness along the base of the bluff 
where Pigeon and Lake Plains meet that a man could not have stood up- 
right in it. 
All these facts lead to the conclusion that the Ohio River at one time 
flowed through Lake Plain and down through Pigeon Plain, entering the 
