Later, at the base of the ice, rock fragments are deposited to form till. Ice begins to melt. Stagnant ice melts. Ice-contact deposits slope toward center of valley. A glacial lake forms in which clay and silt accumulate.
Glacial lake is filled with sediment or is drained.
Glacial streams flow over surface of lake deposits and lay down sand and gravel deposits. Recent stream cuts into glacial deposits and lays down alluvium consisting of silt, sand and gravel.