These markings, known as cup-marks, are among the most common and least understood forms of prehistoric rock art found across Ireland and Britain. They are exactly what the name suggests: small, roughly circular hollows pecked into stone, rarely deeper than a few centimetres. What they meant to the people who made them remains genuinely unknown. What is clear is that someone thought them worth making, and made a great many of them here.

The stone itself is subrectangular and tapers towards the top, standing just over two metres high, with its long axis running east to west. It now sits incorporated into a field wall on the east-facing slope, which is a common fate for prehistoric standing stones in agricultural landscapes; farmers over the centuries found it more practical to build around them than to shift them. The south face carries seventeen cup-marks, the largest reaching up to 17 centimetres in diameter, along with three further markings that are only partially preserved. A separate example of rock art has also been recorded a short distance to the north, suggesting this hillside above the lake was a place of some significance during prehistory, though the precise period of activity is difficult to pin down without excavation.