The site I've been working for years just outside of my desert ghost town where I live has produced in the older sections lots of so-called Bennington marbles and clays. I figure the 5/8" clays are marbles but what about the whopper clays? Over 1". Could they be a part of antique toilet water-flushing mechanisms or something else having to do with valves of some sort? I dug up another big'un today.