I have a ~~9000 year old 'fleshing Stone' found right in my yard here in upstate NY.
I rarely even show it because it "doesn't exist" in the eyes of "conventional wisdom", isn't made of the "correct material" (it's a grade 9 limestone piece - and sharp as hell, with finely honed and dead straight edges), and is from "the edge of the glacier" where no man could or would have lived "when it was made".
Go Figure.
More artifacts exist like that than we realize. I spent a LOT of time, not just in the creek, but looking for arrowheads. On this particualr day, I was playing in a gravel deposit in the edge of the creek and collecting rocks. When I got home, I showed my dad the neat fish-shaped rock I'd found. He laughed. It was an arrowhead, perfect, flint?/quartz?, and beautiful. I didn't recognize it at the time because I wasn't looking for arrowheads-I was looking for rocks. LOL