Eyup Riv!
I must say I've been unable to find Charles Wimpenny's Stone Circle (even with my GPS), but I've got to admit that last time I was there it was covered in snow and the grass was quite long, so it could well have been hidden.
That stone looks interesting - do you have a grid reference for it?
I'm fascinated by that whole Winter Hill/Anglezarke area - the other night I went to watch 'The Hulk' at Horwich cinema and was well impressed by the view of the Pike from there. It's even pretty tempting to develop a theory of alignment with the Reebok Stadium... ;-)
BTW - that quarry you mentioned a few weeks ago - do you have a grid reference for that? I'd be interested to see it, but I'm not sure where it is...
IM