Anyone recognize what this copper disc is from and approximate age? Found in an area with a bit over 110 years of known activity. I don't see anything written on it or any logo that I can make out. It's 2" in diameter and has a tiny lip on the back side. The lip doesn't seem big enough to snap onto anything like a powder/makeup case. It does look a bit like the back side of a wristwatch, but, kinda big for that isn't it? And I don't recall ever seeing one made of relatively thin copper. I don't know why a hole was punched into it. Maybe a kid made it into a pendant?