He discovered a boulder with a series of markings, lines and cuts – which, after being examined by experts, has been declared a significant archaeological find.
Jim McNeil, of South Yorkshire Archaeological Service, said: “I was called in and recorded the discovery, taking photographs.
“I have taken advice from a specialist who considers this to be an important piece of prehistoric rock art. This is the second example of such rock art from Ecclesall Woods, although other examples are known from the Peak District and further north in the Pennines.”
Despite having been examined by experts, the meaning of the carvings is unclear.