
I don't actually how these rocks were formed, or how they came to be where they are. I can imagine both an entirely natural process (boulder falls from above, rolls to a stop where it is today, then erodes into this odd shape) and an entirely anthropomorphic process (a gang of kids or adults rolls a nearby boulder into place, then shapes it with sledges). I'm inclined to favor the natural process, as there's nothing about this rock that looks “manufactured” to me. But who knows? Maybe the perpetrators were drunk!

A couple of years ago, I heard (and I've forgotten where) about a fascinating study done of balanced rocks in our area. Some geologist had a very bright idea: that the balanced rocks could be used as a sort of recording seismograph. It's possible to compute the force (and therefore the size of the earthquake) required to dislodge a balanced rock. From other evidence, one can make a good estimate of when a rock was dislodged. On the other hand, one can also infer the absence of earthquakes from balanced rocks that have not been dislodged. By studying thousands of these rocks all over the southern California and northern Mexico, the geologist was able to develop maps of major earthquakes over the past 150,000 years. The connection: the two rocks above were part of that study.
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