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Title: Bowlders
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The bowlder drift next succeeds in age. This formation is well developed in the west and northern parts of the county and, in fact, underlies all the Grand Prairie district. It consists of tenacious gray and blue clays, obscurely laminated, and holding a considerable proportion of worn and polished pebbles and bowlders. Some of the latter are specimens of the Devonian and Silurian rocks in northern Indiana and Illinois, but a larger proportion are metamorphic or transition rocks from the neighboring country of Lake Superior, or from still more arctic regions. The bowlders and coarse gravel are scattered from near the top down to within five to twenty feet of the bottom of the drift, for these clays were in a soft and oozy condition, and the heavy granite would naturally sink some distance. As a consequence, where bowlders are found on the surface, we may safely conclude that erosive action had carried away the finer matrix, leaving bare the heavy rocks. These, in return, by their number, are a measure of the amount of denudation. Partings of quicksands and thin layers of stone fragments from neighboring strrata are found located at large intervals through the formation, showing that for short spaces during the drift period the great ice-bearing stream from the north was obstructed or overpowered by currents from the east or from the west, thus mingling with the northern drift fragmentary materials from Indiana, Illinois and Iowa. Near the base of the drift and resting on a broken and irregular floor of coal measure rocks, is generally found a bed of potter's clay, intermixed with quicksand and black muck. A marked bed of this latter was found in sinking the West Lebanon shaft. From the soil here discovered wree taken a large number of roots of trees, shrubs and plants of pre-glacial age.


[Page 202-203.]

Date: 1/1/1913
Origin: Past and Present of Fountain and Warren Counties Indiana
Author: Thomas A. Clifton, Editor
Record ID: 00001561
Type: Book
Source Archive: Williamsport-Washington Township Public Library
Date Entered: 8/10/2001
Collection: Williamsport-Washington Township Public Library
Entered By: Leslie J. Rice

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