Friar's Heel The outstanding upright stone at Stonehenge is so called. Geoffrey of Monmouth says the devil bought the stones
of an old woman in Ireland, wrapped them up in a wyth, and brought them to Salisbury plain. Just before he got to Mount
Ambre the wyth broke, and one of the stones fell into the Avon, the rest were carried to the plain. After the fiend had fixed
them in the ground, he cried out, "No man will ever find out how these stones came here." A friar replied, "That's more than
thee canst tell," whereupon the foul fiend threw one of the stones at him and struck him on the heel. The stone stuck in the
ground, and remains so to the present hour.

I have seen the "heel stone" in pictures by never knew how it got its name.