> A likely supposition is that many or most of the
> stone fence or gate-posts on Orkney were originally
> megaliths.
Why is that likely? I think a lot of people would disagree with you there SL. Just because something is long, thin and made of stone doesn't mean it's prehistoric. Stone boundary markers were in use until relatively recently on Orkney (often running to the lowest tidal point where land meets the sea). They're not rare.
Why don't we ask the question, "how many Orcadian linear boundaries, marked by stones, have been proven to be made from prehistoric standing stones?".
> The line I draw (in the sand) is whether I can discern
> the mark of a hardened steel chisel.
That's a good indication that it's been worked recently, but it's no indication of whether or not the stone is an erratic.
Essentially I agree with you though, everyone has their own line in the sand. The problem is that, on this site at least, we're aiming to represent sites where there is at least some evidence of a prehistoric connection. That's pretty nice and vague, but we still get loads of stuff posted that doesn't make the grade.
> Anyone in the mood to purge sites could rifle through...
I'm not in the mood to purge. I'm just trying to encourage some debate. We should all be taking an interest in those sites that fall into the grey zone.
K x