In the pasture at Ballycarroon, in undulating County Mayo terrain, there is a D-shaped depression roughly fourteen metres across and just over a metre and a half deep, its curved side forming a concave inward-sloping scarp that drops to a level base. Ash trees have taken root in the interior, and gorse and brambles crowd the perimeter. The current assessment is that this is a quarry pit of relatively recent date, and that no trace of any original enclosure survives.

The site's complicated paper trail tells the more interesting story. It does not appear on the 1838 Ordnance Survey six-inch map, nor on the later twenty-five-inch plan, but by the 1922 edition a D-shaped hachured area, the cartographic convention for a slight earthwork, was being recorded there, bordered on its straight western side by a field boundary. On that basis it was included in the Sites and Monuments Record in 1991 and in the Record of Monuments and Places in 1997, both times as an enclosure. The designation matters because an enclosure of this kind, in an Irish context, could potentially be a rath, the ringfort type that served as a defended farmstead during the early medieval period, roughly the fifth to twelfth centuries. A possible rath does exist about a hundred metres to the north-east, which may explain why the feature at Ballycarroon attracted attention in the first place. The SMR file eventually noted it as a destroyed enclosure, though the current physical evidence points away from any early medieval origin and towards quarrying activity instead. What looked like archaeology on a map turned out to be, most probably, agricultural industry. The steep external fall on the western side and the remnants of a field fence along that same scarp are more consistent with extraction than with any kind of enclosure construction.