Rippling Sand But No Arrow Heads

The shifting river bed of the Cedar River at the Palisades - Kepler State Park is especially revealing when water levels change. Recently the river has risen and fallen with snow melt and spring rains leaving this undulating sand pattern visible. The river bed is great place to collect rocks including shell and coral fossils, and all the major rock types. Today also yielded a few glass bottle fragments and a tea cup handle. While all the raw materials are present in the river bed for their production we were not able to find any spear points. The search continues. Anybody know a good place to find arrow heads around here? Still, it was just the right way to end a warm weekend. Know that.