There is no mound, no marker, no surface trace of any kind. What exists is an absence shaped by time, and the knowledge that beneath the soil lies a compressed accumulation of discarded oyster shells, the kind of deposit archaeologists call a midden, left by people who gathered and ate shellfish along this shoreline sometime between roughly 1110 and 1340 AD.

That date range comes from a radiocarbon determination taken from oyster shell recovered at the top of the deposit, returning a result of 730 plus or minus 60 years before present, calibrated to that medieval window. A midden is essentially a refuse heap, and shell middens in particular are among the more durable traces of coastal food gathering, since the calcium in shell resists decay far better than bone or organic matter. The site on Great Island was recorded with some precision in 1973 by a researcher named Schlichting, who noted surface indications then measuring approximately 160 feet east to west and 50 feet north to south, a substantial footprint for what amounts to a medieval kitchen dump. By the time the site was mapped using the 1933 Ordnance Survey six-inch sheet, it was already being defined by a broken line to the west of a lodge and south of the shore road, which suggests its outline was already somewhat uncertain. Today even those surface indications are gone. Two further shell middens lie further west along the same shoreline, hinting that this stretch of Cork Harbour was a productive and regularly worked coastal resource across the medieval period.