The island itself, lying off the Connemara coast, was permanently evacuated in 1960, and most of what remains there now does so without explanation or ceremony. This enclosure is no different: roughly rectangular, built from drystone walling that has largely fallen in on itself, it raises more questions than the stone can currently answer.

When archaeologists examined the structure in August 1984, they found a near-square enclosure measuring about 13.8 metres east to west and 13.3 metres north to south. The double-faced drystone wall, a construction technique in which two lines of facing stones contain a rubble fill between them, stood no higher than 30 centimetres at its tallest point. An entrance on the south wall, just 70 centimetres wide and flanked by two upright stones, suggested deliberate and careful construction rather than a casual boundary. Inside, the ground was uneven and sloped toward the south-south-west. A second internal wall, flag-revetted and running roughly north to south through the centre, may once have divided the space into two areas. At the south-west corner, a small subcircular annexe, only about 2.4 metres across, adjoined the main enclosure, with the collapsed bank extending from there toward the cliff.

The identity of the structure has become a subject of active archaeological research. Work published in 2010 by Kuijt and colleagues raised the possibility that it may have functioned as a burial ground, with the south-western annexe potentially the remains of a clochan, a type of small dry-stone beehive hut associated with early Christian monastic sites in Ireland. If that interpretation holds, the enclosure would fit into a broader pattern of early ecclesiastical activity on the offshore islands of the west coast, where isolation and the sea shaped a particular kind of devotional life. For now, though, the structure sits unresolved on its hummock, its entrance uprights still standing, waiting on further fieldwork to say what it was.