Abandoned lake beds in Ohio have been studied and mapped. A dozen have been examined, and five or six other areas have been studied; no evidence of postglacial lake occupation has been found.
The best evidence of the former presence of a lake is in the silts. Occasional traces of shore lines, four deltas, and a few examples of outlet channels have been found.
Tilting is shown by the distribution of the silts. They have been mapped up the slopes as high as they can be found. Erosion is recognized as a modifier of this distribution. Deltas and outlets identify tilting.
The direction of tilt is consistently nearly southward. The amount of tilting varies from about 2½ feet to 4 feet per mile.
Care has been taken not to mistake moraine and outwash terraces for shore lines. Both are recognized in valleys of central Ohio.