Tiompan, is it ref 454 in PRAWR you're referring to? If so, I agree the grooves are a little sus'. Whenever I'm up that part of Middleton, I always go for a skeg at that rock to see if I can make a decision one way, or t'other, but I never can. Its those pesky cup marks on the other side that make you think, 'maybe the groves could be manmade'…
Ref 462 is a bit of bugger too, a big rock with definite cup marks, some parallel & meandering grooves. Again, I'd put my money on most of the grooves being natural, but the cup factor always makes for a big ? I think Boughey & Vickerman had the same problems deciding too.
Theres another unreferenced rock too, that has 4 parallel grooves of differing length on its S facing vertical, it had Paul Bennett & myself pondering its merits.
