This river rock is something that hadn't occured to me. I never thought about it because the surface is so finely polished. I assumed it was by man. It certainly is possible though.
It was in with my fathers things when he died so I dont have any ID on the location or circumstances.
Looking at it further, the length and the formed shape have a very intentional look about them. It is a very clear and level arch on each side. The polished side looks even across as well.
If it wasn't such a wierd break and not so symetrical you would have me.
Truthfully I wouldnt know how and indian would break it like that either though. To me it shows points where it was chipped to break off the stone but it would be alot of work for a primitive and I dont know how he would do it.