I know a lot less about pre-history than I do about history. (Although both are fascinating.) So here's where some of you archeo-paleo folks may be able to help me out,....
I came across this rock (above) in a mostly unspoiled area of the San Joaquin Hills, near UCI, this weekend. For some reason, the terrain already had me on alert for artifacts. So, is this an over-200-year-old mortar hole/grinding rock (for grinding acorn meal)? Or is the divot in this rock something much more recent?
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It may be possible that even an expert couldn't tell from a photograph. In that case, how does one know the difference when you're actually looking at the rock? I'll be curious to see what answers appear in the "comments" section in the coming days. Thanks in advance.