Paulus wrote:
It looks suspiciously like its come from a neolithic or Bronze Age tomb - probably one close by. It might be worthwhile seeing if you can get hold of the field-name listings for the region all round Lower Rivington Reservoir and see if anything stands out. Two of 'em already look suspicious and worthy of checking: the Headless Cross and Roscoe Lowe.
Maybe a search on old maps or in the local library may yield something. We can forget Headless Cross it’s the remains of an Anglo Saxon wayside cross, see http://www.megalithic.co.uk/article.php?sid=11076 Roscoe Lowe would be within the grounds of the Anderton Centre where the Stone is sited. It is private property but I don’t see any problem taking a look around, they seem quite friendly there.The thing that puzzles me is why only the one carved stone in the area, this has set me wondering whether it could be a stone brought in during the construction of the reservoir; it does however appear to be of the local millstone grit.
I’m sure there’s a lot still to be found in this area, the problem is finding it due to the blanket of peat which covers the whole Winter Hill / Anglezarke area, and the remains of the extensive mining & quarrying which confuses things still further.