Damn. I go away for the weekend and miss people talking about one of my favourite topics.

The whole RA/IA thing seems even odder considering people used to say the carvings were IA because they were in a hillfort. As far as I know, Dod Law is the only one in Northumberland that's been excavated, and I think the earthworks were very IA, but that there may have been an earlier enclosure beeath. There's certaintly an enclosure just off to the side, but I don't think it's been dug.

Possibly vaguely relevant to the matter, especially to Roughting Linn, as they look a bit similar, are the BA earthworks in Coquetdale, usually said to be territorial marker boundary thingies.

Whatever the chronologies, I don't think the relationship between RA and earthworks is just random chance.