Kevin, your are welcome :D
The following picture shows the distal bones from:
Bison bison I have to admit, now that Tippit has mentioned it, that I like his idea of the end of a radius too -
proximal end though. This way the deep lobes around the articulation surface and the obvious lack of rough surface and holes from many vessles through the bone, could be explained.
Estimating the size I think it could be no Bison anymore. A Deer then?! Shot from the right, quatering away, but the hunter missed a deadly shot by an inch or two ... Bad luck!
We need more pics!
DW, BTW: Sure a great find - if I failed to say that - sorry! But I somehow like this sort of puzzle - and get carried away