Monday, March 22, 2010

Prehistoric food processor? Or just a rock?

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?
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.


Doug said...

The feature/depression on the rocks does have the appearance of being a shallow bedrock mortar (BRM). The boulder looks as though it has been displaced by farming or discing activities. It does not appear to be in situ. There are visible disc scars, which most likely made by a steel implement. Let me know the area you located this, and I may be able to tell you if there is a report archaeo. site there. Fun find Chris!

Lucy said...

I can't tell from your picture. If it was up here, I would guess that water got into a crack, froze in winter and 'popped' out a wad? How prehistoric could it be? Ice Age?

Chris Jepsen said...

Doug: Thanks for the info! That makes sense with what I saw in person. Since I don't like to announce an artifact's location to the public, I will email you with the location privately.

Lucy & Dick: The Shoshonean peoples were living here when the Spanish arrived. And 3 or 4 thousand years ago an entirely different bunch of folks were living here. I'm not sure who moved where and when. As a non-expert, I'd guess this BMR (I learned a new acronym!) is hundreds, rather than thousands, of years old.

And no, we don't get much opportunity for frozen rocks here in O.C. :-)