> The egg-stones all have the same structure and the same source - they are eroded from the hillside. <

So let me try and get this straight :-) There are at least <i>two</i> worked Egg Stones all of which came from the same hillside (the hillside in question being Glastonbury Tor?). The Egg Stone in the Glastonbury Abbey grounds being hauled a mile or so from the Tor. Nat's Egg Stone, now halfway down the Tor, presumably being chucked there from the top of the Tor at some point.

This is all beginning to sound like a dropped stone (no pun intended) for the <b>Circles under churches</b> Thread...