There are two stones here, nine yards apart. Perhaps they're natural, I can't find a photo.
Hedgeley Moor was the site of a Yorkist/Lancastrian battle in 1464. The Lancastrians were led by Sir Ralph Percy. When Percy copped a mortal blow, well he was supposed to have leapt the distance between these two stones. One supposes on his horse, though how boring is that.
Sir Walter Scott measured the distance "and would have said and almost sworn that it was but eighteen feet." There's nothing like a bit of exaggeration - but perhaps a passing TMA reader should go and check.
Percy was supposed to have actually died across the road at the spot where 'Percy's Cross' now stands.
(Mentioned in Chatto's 'Rambles in Northumberland' (1835) p223, and Scott's 1827 journal.)