There isn't a lot of information on it. Legend around town has it that it predates Columbus and vikings put it there. But after a little research it looks like most scholars aren't even sure what it is of, let alone who did it. The general consensus is that it is of a ram, a goat, or an owl, and that it was carved at least before the 1880s.
I remember someone saying something about another carving like that someplace in the area. If there are others in that area, it could possibly lead to something.