Thanks for that Branwen (though I don't think I have any special talent for reading stones :-)

The 'playback' theory for stones is something that is interesting though - ie that some stones (bricks and mortar included) might be able to absorb events (especially intense events) and play them back when conditions are right (and people are sensitive or 'intune' enough to perceive them).

I don't think any of this is 'supernatural' (not in the spooky sense anyway) but as Mr Squid said elsewhere, it would be foolish to assume that we know all there is to know about the universe, and things super natural are perhaps simply things we are yet to understand.