Mr. C- L- told Mrs S- the large slit at the top of the Hawk Stone was worn by the friction of the chain when witches were chained to it and burnt.
Scraps of English Folklore, XVII. Oxfordshire
Grace Heuman; Elsie Corbett; A. A. Antrobus
Folklore, Vol. 40, No. 1. (Mar. 31, 1929), pp. 77-83