I'm not at all sure that this is the right place to discuss a Portal comment. I do agree entirely with all that Kammer has written on this thread. Yes - an erratic can be used as a prehistoric standing stone and then at a later date that same stone can be shaped and used as a gatepost. Burden of reasonable certainty if not proof?

We even had a comment from a guy who claims to have made one of Orkney's "prehistoric" features! See http://www.megalithic.co.uk/modules.php?op=modload&name=a312&file=index&do=showpic&pid=8945&orderby=dateD