1. If the rings in this formation were caused by interaction with groundwater (which does not conflict known processes)
2. If, as I pointed out in a post below this formation was exposed to weathering only recently (due to sharp edges being present that would be attacked first by erosion).
3. We have found a completely natural explanation for the formation.
These rocks were underground for an extremely long time interacting with groundwater, then were recently (keep in mind that I mean recent in a geologic sense) exposed and are now starting to be weathereed. The recent exposure would be due to the erosion of the soil by wind or water. (Most likely water runoff because the trees would somewhat protect from the wind)
I don't know about you guys, but this seams like a very rational and plausible solution to me. Let me know what you think.