any i.d. idea on this piece?

[tomthumb]

found afew new pieces and this square block that is ground smooth on both sides. Any takers?

[The Grim Reaper]

Nice looking finds. Your square rock could be a few things. It could be a very worn out Metate. I'm not sure how prevalent the Adena culture was in your area, but it also could be an Adena Tablet. And it could also be a naturally formed stone. Do you see any incising of any kind on it?