This was giving a solid half dollar signal so I had to dig it. It was about 10 inches down in an old road bed. Turns out...it's an old flashlight from the 30's or 40's.
I've decided to go back to the site asap and dig every signal. The place dates back to the 1890s so there is no telling what I may find. It appears to have never been dug.
Back a hundred or so years ago, I worked at a trucking depot second shift, hooking trucks to trailers. I was issued a flashlight and could only get a new one if the old one was broke. When one got so bad that I had to shake it to make it work, I had to take it to the tool room for a replacement. Tool room guy shook and shook and it finally came on. Gave it back and said it was fine. Bring it Back when its really broke" he said. Took it out, laid it on ground and ran over it with tractor trailer. He replaced it! It looked a lot like yours.