Date of this Version
The Journal of Geology 60:6 (Nov 1952), pp. 575-585.
Studies of drift thickness and character currently in progress in Indiana indicate changes in drainage that have occurred in Indiana and some adjoining states since the beginning of the Pleistocene epoch. After late Tertiary (Lexington) peneplanation the master-drainage line, the Mahomet-Teays Valley system, became entrenched about 200 feet below its former level before it was ponded by Nebraskan ice and diverted into a new course. During the Parker cycle, which was interrupted by glaciation, the present physiographic features of southern Indiana and their now buried extensions to the north became recognizable. Static rejuvenation then was a major factor in erosion of the "Deep stage" of the Ohio Valley. Reversal of the pre-Illinoian Miami Valley probably resulted from this glaciation also. Further ponding of the Mahomet by Kansan ice and diversion of its drainage down the Wabash Valley is suggested as the origin of the "Deep stage" along that stream. Present drainage in central Indiana is a result of modifications produced by Tazewell and Cary glaciers.