What makes it worth pausing over is its upper surface, which is covered almost entirely in cup-marks, the shallow, roughly circular depressions that are among the oldest forms of human mark-making found across Atlantic Europe. There are approximately thirty-four of them here, ranging from 3.5 to 8 centimetres in diameter, accompanied by around thirty smaller pock marks. The boulder measures just over a metre in length and less than a metre wide, yet nearly every available inch of its flat, tilted face carries some deliberate impression. It sits at around 118 metres above sea level, and the valley of the Owencashlia river opens out to the north-east with views toward Tralee Bay, though Glanteenassig Forest now closes off much of the wider panorama.

Cup-marks are a prehistoric art form found widely across Ireland and Britain, typically associated with the Neolithic and Bronze Age periods, though their exact purpose remains a matter of scholarly debate. They may mark territories, ritual sites, or astronomical alignments, or they may have served purposes we can no longer recover. The Glanteenassig example was first documented in J. Cuppage's 1986 archaeological survey of the Corca Dhuibhne region of the Dingle Peninsula. Cuppage noted that the cup-marks here are notably irregular and uneven compared to other examples, and that heavy weathering of the sandstone has left the surface extensively pitted, making it difficult in places to distinguish deliberate carving from natural erosion. Some of the smaller, less well-defined marks may be the work of the elements rather than human hands. The boulder now sits partly covered by sod around its edges and moss along its north and south sides, blending quietly into its surroundings.