The original reference, dating back to 1889, described cupmarks; small, circular depressions carved into natural rock surfaces that were commonly created by ancient peoples across Ireland and Britain. These mysterious markings, typically dating from the Neolithic to Bronze Age periods, often appear in clusters on exposed rock faces and are thought to have held ritual or territorial significance for early communities.

Despite the tantalising historical reference by Kinahan in 1889, modern archaeological surveys have been unable to verify the presence of these cupmarks at Coolboy Big. The area features extensive rock outcrops that would have provided ideal canvases for prehistoric artists, but dense vegetation now blankets much of the exposed stone, making thorough investigation challenging. This situation isn't uncommon in Irish archaeology; many sites mentioned in Victorian antiquarian texts have proved elusive to modern researchers, either due to misidentification, destruction, or simply the passage of time obscuring once visible features.

The search for these cupmarks forms part of the broader Archaeological Survey of County Donegal, a comprehensive project that catalogued the county's archaeological heritage from the Mesolithic period through to the 17th century. Compiled by Brian Lacey and his team in 1983, the survey represents one of the most thorough archaeological inventories in Ireland, documenting everything from ancient tombs to medieval castles. While the Coolboy Big cupmarks remain unconfirmed, their inclusion in the survey ensures that future archaeologists and local historians remain aware of this potential site, keeping alive the possibility that careful vegetation clearing or new survey techniques might one day reveal the elusive rock art described over a century ago.