My friend found the following as a child in Neosho, MO in 1975 or so. His Dad had burned some rubbish and he was playing with his GI Joe (with kung foo grip) in the ashes a few days later and found it. He was asking me about it, but I told him you folks would have a better idea. Thanks!
It could be called a couple of things. Possibly an adze used for light chopping or a scrapper used for well you know or even a pre form that was being reduced down into another shape. I would vote a hand adze and a very nice prehistoric tool at that. Loved that little guy with the kung fu grip!
Hope this helps google maybe hand adzes for more examples.