It is roughly circular, about thirteen and a half metres across and nearly two and a half metres high, and it is made almost entirely of shells, principally periwinkle and limpet. This is a midden, the accumulated refuse of countless meals, the kind of deposit that forms when communities return again and again to the same spot to eat shellfish and discard the remains. Over time, the heap grows, the grass claims it, and what was once rubbish becomes archaeology.

The site is known locally as Toit Chonáin, a name recorded through local knowledge rather than any official gazetteer. It may be the kitchen-midden mentioned by Kinahan in 1872 and again by Brunicardi in 1914, both of whom were writing at a time when such deposits were attracting serious antiquarian interest across Ireland and Britain. Kitchen-middens, as they were called by the nineteenth-century researchers who first studied them systematically, are amongst the most direct evidence we have of how coastal people ate and lived, sometimes stretching back thousands of years. The shells themselves can be dated, and their species composition tells you something about which parts of the foreshore were being exploited and how intensively. At Kerraunngark, the dominance of periwinkle and limpet points to inshore gathering of the kind that requires no boat and very little equipment, just patience and a low tide.