Link

The Calderstones
Cup and Ring Marks / Rock Art
Google Books

The Transactions of the Historic Society of Lancashire and Cheshire for 1865 has an article by Professor J Y Simpson about the carvings (with drawings). I guess the feet hadn’t been spotted yet. Perhaps they come under the description of the stone which is “too much disfigured by modern apocryphal cuttings and chisellings to deserve archaeological notice.”