Since you haven't been finding any arrowheads, grab a large block of flint (at least 1ft across), make it into an extra large arrowhead, cut off a branch for the shaft, assemble together, then claim it's for hunting the ellusive allicrocosaurus.
lol. Faking it isn't satisfying, and oddly enough, there is no flint here. There are no rocks. There is only limestone. I seriously think this was all a lake when the natives lived here. It's the only explanation. Other land owners have found plenty.