I don't think it's a line that can be drawn. It's too wiggly.

But those cups are on this side of that line. Even if they have no provenance, the mere possibility that such OOPArts as cup marks down south, might have pre-historic origins is something worthy of being bounced about here. Correct me if I'm talking bollox, but you don't get rock art down your way do you? So whilst some might say this makes them unlikely to be pre-historic, I'd argue that it would be worth getting someone to try and check, because if they are its a doozy.

They remind me of the things I saw on the telly at Zennor museum, which in turn reminded me of Bullauns. But then I do like cup marks. I'll see them everywhere given the chance.

Infact, what's that over there on the floor by the sofa?

Nah, that's just a mark left by a cup.

Now that* was a low quality pun.