Nice finds on the artifacts, Bruce.
I can't tell if that round rock has been used as a hammerstone or not,
but it would make a good one. The flat altered area on the rock you are
wondering about looks to be natural, not from any human activity. It's
like a "shear" in geology. Long before this rock became the round cobble
it is now, the rocks moved, due to pressure or an earthquake or something
and created this shear. The area looks "melted", and that can only happen
naturally with lots of pressure, which creates heat.
I don't think it's an artifact unless there are other areas on it that have been
worn smooth and show wear.
JoeM
