That is wild. A couple of our friends when I was living in Montana would go to the east side of the state and excavate around buffalo jumps. They had some neat skulls. I'm thinking they had also brought home some pottery shards and stone implements, but can't remember 100%. Another gentleman that is a friend of my dad's (actually he lives right up by Guy & Ellie) had hundreds of arrowheads he had found. When I was a kid, he cleaned out all of the ones that weren't perfect, i.e. had a chip or broken ear or something. He gave me something like a couple hundred imperfect arrowheads, most of which I have since handed off to young people that took an interest. I've found a few arrowheads myself, but small and imperfect. I did find one good spear point once myself. It's about three inches long and it's pretty nice, but does have a chip. The undamaged ones are hard to come by!