Not a dramatic find by any obvious measure, and yet this modest accumulation of discarded shells, broken pottery, and animal bone has turned out to be one of the more revealing scraps of evidence about how people lived at this famous hillfort on Inis Mór, the largest of the Aran Islands, roughly three thousand years ago.

A midden is simply an ancient refuse deposit, the prehistoric equivalent of a waste pit, and this one was uncovered during research excavations at the south-eastern end of Dún Aonghasa's middle enclosure. The excavated area measured just six metres by four, and even that small patch represented only what erosion had left behind; the original deposit would have been larger. Where it survived best, pressed against the stonework of the enclosure's primary wall phase, it reached up to 0.45 metres in depth before being sealed beneath the foundations of a later phase of walling. The contents were overwhelmingly limpet shells, with smaller quantities of animal bone, some eroded cooking ware, and a single plain, unperforated bone pin. What makes this accumulation particularly useful to archaeologists is its chronological precision: a radiocarbon date obtained from animal bone placed the midden's use within the period 1050 to 890 cal. BC, squarely in the Late Bronze Age. Its stratigraphic position mattered too. A thin scatter of refuse found beneath the foundations of a nearby structure confirmed that the midden was already there before that building went up, anchoring it to the earliest phase of occupation in this part of the enclosure.