Decided to take my poorly hand for a bit of fresh air.
This is the Devil's Stone near the top of Addlebrough. According to ye-olde folklore (according to ye-less-olde interweb), the Devil and a giant had a fight - throwing stones at each other. The Devil was on the banks of Semerwater and the giant on the top of Addlebrough. This is the Devil's stone, the gouges are supposed to be from his fingers. There are two stones on the banks of Semerwater, thrown by the giant.
There isn't really a footpath to the stone, so I had to make one up, ended up on the wrong side of the wall - d'oh! Didn't want to clamber over 'cos it looked a bit fragile.