Does it matter why it lay in the weeds for a week and a half? That doesn't necessarily mean it's finders keepers. If you can identify that it is a phone junction box - wouldn't that, by definition, mean it belonged to the phone company? It could lay there for years and still belong to the phone company. Even if it was laying on your land, that wouldn't make it yours - that's why phone companies (and gas, and electric, and cable) have easements. That gives them permission to go on your land and service their equipment.