The site is a midden, essentially a refuse heap of shellfish remains left behind by earlier inhabitants or visitors, and it only came to light because rats and birds had been burrowing into the soil. That accidental excavation revealed an exposure of roughly eight metres by four metres on the sheltered northern side of a raised rock outcrop, where a thin covering of soil had preserved the deposit.

What emerged from that disturbed ground was largely limpet shells, the kind of modest, reliable food source that coastal communities across Ireland have relied upon for millennia. Mixed in were smaller quantities of winkle and dog-whelk shells, along with some burnt stone, which sometimes indicates the heating of water or food preparation nearby. The presence of multiple shell species and burnt stone together suggests this was a place of repeated use rather than a single visit, though the record does not extend to dating the deposit or identifying who left it. The site was recorded by M. Gibbons, whose fieldwork brought it into the formal archaeological record.

Fox Island sits within Crompaun Bay and is accessible at low tide, meaning the window to reach it is governed by the sea rather than any gate or opening hour. The midden itself lies on the northern, more sheltered face of the island's rocky rise, where the thin soil cover made preservation possible and animal disturbance made discovery likely.