OK on an old farm from about 1900's to 1930ish has an old potato cellar.now from the rite back corner of the old cellar about 15 to 30 feet is a circular hole built up w/ stone, which is between the old house foundation which is about 50 to 60 yards away. my question is, how do i tell if that was a cistern OR a well? i would think that either has different aspects of MDing. somehow. wouldn't a cistern be closer 2 the house. ohh this hole is uncovered and about 10 to 15 ft deep today. any help would be great. diameter is bout 2 ft