I have no idea how to do this. I posted it in another forum but nobody really could tell what it was. No definitely didn't find in the backyard. We always go to riverbeds and walk around. Thanks for looking though.
Yup you posted it here and I was the one who thought it could be a mold to form metal.......not sure but it looks like the metal is atypical to the stone. Not to mention how it is overflowing its cavity....................GTP(Chris)