Scratch circles and circular purported ammoglyphs: Novel observations from the Cape south coast of South Africa - Charles W. Helm; Robin M. Catchpole; Hayley C. Cawthra; Richard M. Cowling; Jan C. De Vynck; Mark G. Dixon; Renée Rust; Willo Stear; Guy H.H. Thesen (Proceedings of the Geologists' Association, 2024)