Funny how the best collection of US potlids ever resides down under. Or Deown Undah...thank goodness you don't have many earthquakes round your part of the world. Otherwise those babies would be shake and bake.
Oh, okay. A friend of mine found a round one in the creek several years ago. Sold it on ebay, I believe. Only pot lid I've seen around these parts in my 40+ years of collecting. I guess nobody brushed their teeth around here back then.