The earliest Pleistocene glacier to enter the northern United States has been termed the Nebraskan glacier. This glacial advance occurred perhaps two million years ago. Consequently, deposits from the Nebraskan glacier are greatly weathered and highly dissected by erosion. No confirmed deposits attributable to the Nebraskan glacier have been found in Ohio. Such deposits, if originally present, were destroyed by later glacial advances or removed during a long period of erosion.