They are easy to miss, and that is part of what makes them worth knowing about. Carved into their flat surfaces is a vocabulary of prehistoric marks, cup-and-ring motifs, that appear across Atlantic Europe during the Neolithic and Bronze Age: a small circular depression, or cup, cut into the rock and surrounded by one or more incomplete, open-ended rings, sometimes with a groove radiating outward from the centre like a spoke. Nobody has settled on a definitive explanation for what these carvings meant to the people who made them, but the consistency of the style across vast distances, and over long periods, suggests they carried real and repeated significance.

The larger of the two surviving slabs, a rectangular block of smooth, fractured sandstone measuring roughly 1.22 metres by 0.4 metres, carries an unusually dense collection of motifs for its size. These include two cup-and-rings, three cup-and-two-rings, and one cup-and-three-rings, along with six plain cupmarks and several grooves; one groove runs along the centre of the slab for almost half its length before splitting at a right angle. The penannular rings, meaning rings left deliberately open rather than fully closed, appear throughout. The second slab, slightly larger at 1.3 metres by 0.5 metres, concentrates its decoration toward one end, where a cup-and-two-ring motif with a radial groove is intersected by a curved groove that connects to a further cup-and-ring and cupmark, enclosed in an arc, a more complex arrangement than is typical. A third stone was recorded at this location by a researcher named Cooke in 1906, including a cup-and-ring linked to a subrectangular grid pattern, but that stone can no longer be found. The larger slab is also known to have been moved from its original position during modern land clearance, which means the arrangement visitors see today is not necessarily the one that existed in prehistory.