So obviously in certain areas, they can be fairly sure that if they stumble across certain things it could be an archeological find, and should contact some form of archeological society, museum, or other research authority....
But I'm imagining a farmer tripping over a rock, calling the cops, and the cops showing up to arrest the stone.
Also I'm not sure what they do in situations like this, but if they wanted to move them, I'd want to keep one.