This is a boulder-burial, a megalithic monument type found mainly in the south-west of Ireland, in which a substantial capstone is propped above the earth rather than used to roof a proper chamber. What makes the example at Knocknageehy quietly arresting is not just its form but what is carved into it: seven cup-marks, shallow circular depressions pecked into the upper surface of the stone, a type of prehistoric rock art found across Atlantic Europe whose precise meaning remains genuinely uncertain.

The boulder itself measures roughly 1.6 metres by 1.6 metres and stands about a metre tall above its supports. It sits on the southern side of a valley carrying a small river that drains south-westward to Rosscarbery Bay, a detail that places it within a landscape probably well-settled and traversed during the Bronze Age, when boulder-burials are generally thought to have been in use. The cup-marks on the upper surface are particularly notable. Rock art of this kind is not always found in association with funerary monuments, and its presence here raises questions that the archaeology has not yet fully answered. Were the markings made at the same time as the monument was raised, or earlier, perhaps already on a stone that was chosen in part because it carried them? The record, drawing on Roberts's 1988 survey and the published inventory of West Cork archaeology, does not resolve this, and perhaps that is part of what makes the site linger in the mind.