It measures roughly 4.6 metres in length and about 0.2 metres thick, and packed into it are periwinkle shells, burnt stone, and fragments of charcoal. What you are looking at is a midden, the accumulated refuse of people who ate shellfish here, built fires, and left behind the evidence of both. Middens of this kind appear all along Ireland's Atlantic coastline, ancient kitchen deposits that erosion eventually cuts open, turning a cliff face into an accidental archive.

The story of this particular deposit has a small wrinkle. When a researcher named Keary examined the site in the early 1960s, publishing his observations in 1965, he found a considerably more extensive deposit nearby, one composed mainly of oyster shells rather than periwinkles. Keary raised the possibility that this larger accumulation might be of natural origin rather than human activity, which complicates the picture somewhat. Oyster beds can and do build up without any human involvement, and distinguishing a natural shell accumulation from a deliberate midden is not always straightforward. The periwinkle-rich band with its burnt stone and charcoal is harder to explain away as natural; burning implies human presence. The two deposits may represent different periods of use, or different activities along the same stretch of shoreline, and that ambiguity is part of what makes the site quietly interesting.