The recession of the late Wisconsinan ice sheet from central Maine was characterized by several modes of deglaciation. Below the limit of marine submergence in the Augusta-Skowhegan area, the retreat of the ice margin is documented by end moraines. A DeGeer-type esker system and accompanying marine deltas were deposited in a succession of narrow, topographically controlled zones of stagnant ice that bordered the active ice margin.

Immediately inland from the marine limit, glaciofluvial deposits were graded to the sea. Examples occur in the Pleasant, Piscataquis, and upper Kennebec River Valleys. The large volumes of these deposits and the presence of morphosequences suggest that they were derived from active ice standing a short distance inland from the sea. However, in certain areas, as between Dexter and Guilford, melting of large stagnant ice blocks produced little or no waterlaid sediment.

Moraines are also present above the marine limit although their significance in determining ice-marginal positions is not well understood. They are particularly characteristic of basins underlain by phaneritic plutonic rocks. Glaciofluvial and lacustrine deposits in northwestern Maine and the deposits of small cirque glaciers on Mt. Katahdin are among the youngest glacial deposits within the study area.