Just south of Johnstone, where the road goes through Craigston Wood, is a sandstone outcrop in an area that has been extensively quarried. Carved into the surface are several cup marks, at least four of which have single rings carved around them. One of the rings was added, or at least "enhanced", in modern times.
There are other modern carvings near the ancient art, including an arrow and letters, plus plenty of modern painted graffiti.