Is anyone else as flummoxed as I am as to what the hell are the Gamel Rock Markings posted by Phil? http://www.themodernantiquarian.com/browse.php?site_id=1802 When I first saw the pics they reminded me of those holes left after geological surveys. You know, where they use a tube like drill then fit a thingy over the cylinder in the rock which marks its orientation , then they break it off and take it back to the lab for tests.
Then I saw the one with the 20p piece... well after a couple of minutes with a pair of dividers (they kept on sliding off the screen), borrowing a coin, marking dots on a bit of paper and a little calculation.... they are about 400mm (16in) across!!
Even with modern diamond tipped drills I don't think these could be done with a hand held machine which pre-supposes that some kind of gantry must have been erected. Was this some kind of experiment done to test a drill and machine? I can't see them being that ancient as they seem too perfect. Any thoughts?