Glacial Lacustrine/Marine
Generally fine textured sediments deposited in glacial lakes which have now drained or filled with sediment.
Large areas often well identified (Taunton, Hitchcock, Sudbury).
Notes:
Many lacustrine areas have sandy material deposited over the silts and clays. It is important to dig deep enough o confirm the fine textured sediments, look for signs of wetness from the bottom and see if it connects to the surface.