During excavations in 2001, led by Peter Woodman from University College Cork and Nicky Milner from Newcastle University, two sites were investigated along the clifftops at Castlequarter. These shell middens, composed primarily of oyster shells, represent the discarded remains of countless meals consumed by coastal communities centuries ago.

At the first site, four test pits were carefully excavated within a surviving section of midden that stretched 25 metres in length and up to 5 metres wide. The archaeologists uncovered a layer of shells reaching 20 centimetres thick in places, with intriguing evidence of burning beneath the shell deposits, suggesting cooking or other activities took place here. Interestingly, when they dug a test pit in the adjacent field, no trace of the midden remained; a telling sign that what survives today is likely just a fraction of a much larger deposit, gradually worn away by centuries of farming on one side and coastal erosion on the other.

The second site, located roughly 50 metres further west, revealed a similar patch of oyster shells with comparable thickness to the first location. These modest surviving portions, tucked between field boundaries and the cliff face, serve as tantalising glimpses into the dietary habits and settlement patterns of Ireland's coastal inhabitants. Though much has been lost to time and the elements, these shell middens remain as enduring markers of human activity, preserving evidence of ancient meals and gatherings along Donegal's dramatic coastline.