These cup-marks, as archaeologists call them, are among the simplest and most widespread forms of prehistoric rock art found across Ireland and Britain, small bowl-shaped depressions worked into stone whose precise meaning remains genuinely unknown. What makes the Carrickmines examples quietly remarkable is not their grandeur but their circumstance: they were found not through dedicated survey but because a motorway was being built directly over them.

The boulders, three in total and recorded together under the site reference DU026-145/146, came to light during archaeological investigations along the route of the South-Eastern Motorway scheme, work that was carried out on behalf of Dún Laoghaire-Rathdown County Council and documented in a substantial four-volume excavation report compiled by T. Breen in 2012. One of the three stones, described in detail by Dr Muiris O'Sullivan, is a slightly rounded granite boulder measuring roughly 0.93 metres by 0.84 metres, triangular in outline, with a gently convex upper face. On that face sit four definite cup-marks and two further possible examples. Three of the definite marks run in a loose line parallel to the edge of the stone; the others are arranged more freely across the surface. A fault line runs across one side of the boulder, and one cup-mark falls directly along it, raising the question of whether that particular hollow is the work of human hands or simply the result of natural geological stress. It is recorded, carefully, as a possible rather than a confirmed example.

Because these boulders were excavated as part of a road scheme rather than preserved in situ, they are no longer accessible at their original findspot. Anyone with a serious interest in the material would need to consult the Breen 2012 report or contact the relevant heritage bodies for information on where the stones are now held. The record itself, maintained through the work of compilers Geraldine Stout and Padraig Clancy and revised by Caimin O'Brien, is what survives as the primary means of engaging with this find. It is a reminder that prehistoric archaeology in Ireland is frequently encountered not in dramatic upland settings but in the path of infrastructure, discovered just in time, or sometimes not quite.