A midden is essentially a rubbish heap, but one that carries considerable value to researchers, since the discarded shells, bones, and other debris left behind by earlier communities can reveal a great deal about diet, season of occupation, and the rhythms of daily life in coastal settlements.

These particular deposits sit to the south of Cill Charna, an ecclesiastical settlement at Cill Éinne, and were described by the writer and mapmaker Tim Robinson in 1980 as little huts and middens of seashells hidden by thickets under the cliff-face. The association with small huts suggests the area may have served some kind of seasonal or ancillary purpose connected to the nearby religious site, though the precise relationship between the two remains unclear. Further concentrations of shells have also been recorded closer to an old reservoir to the southwest of the same area, adding to the sense that shellfish gathering was a sustained and geographically spread activity here rather than a single isolated episode.