Between Honiton and Sidmouth is an inn called The Hunter's Lodge (more recently The Hare and Hounds), and opposite the house is a block of stone, over which hovers a gruesome mystery. It is said that in the dead of night the stone used to stir in its place, and roll heavily down into the valley, to drink at the source of the Sid, and, some say, to try to wash away its stain. Human blood has given it this power--the blood that gushed upon it when the witches slew their victims, for it was once a witches' stone of sacrifice.
From 'Devon, Its Moorlands, Streams and Coasts' by Rosalind Northcote (1898).
There are lots of barrows up here. And there's a bit of megalithic style folklore. But where is the stone?
A rock is set up at a four-crossroads on Gittisham Common. It is called the Witch's Stone, for it is said that witches used to sacrifice babies on it. There is also said to be a treasure buried beneath it, and whenever it hears the church bells striking midnight, it descends to the River Sid to drink.
From p153 of The Folklore of Devon
Folklore, Vol. 75, No. 3. (Autumn, 1964), pp. 145-160.