What is this?

[Rww1987]

Does anyone know what this is? I found it in the river the edge is all the way around it.

 

[rock]

Well this has turned out to be a long theory type of thread. I will throw this one to ya and we will see where it goes from here. It looks like a "Stone Core Tablet Flake" that has been altered to a tool to me. These type of large flakes came in many styles. Thanks, rock