At Ballynacarriga in County Cork, advance excavation work carried out in 2001 uncovered something quietly puzzling: a roughly rectangular arrangement of pits, shallow features, and post-holes sitting inside a pre-existing enclosure. What made the find particularly interesting was not the structure itself but what lay beneath it.

The rectangular arrangement, thought to represent the upper north-western corner of a building, had cut into an earlier circular structure at its north-eastern edge. In archaeological terms, when one feature "truncates" another, it means the later construction physically interrupted or destroyed part of what came before, which establishes a clear sequence: the circular structure came first, and the rectangular one came after. Circular structures within enclosures are a familiar pattern in Irish archaeology, often associated with early medieval settlement, though the precise date and function of either phase at Ballynacarriga were documented by Noonan and colleagues in reports published between 2003 and 2004. The two overlapping phases together suggest the site was occupied, modified, and repurposed across more than one period, with later inhabitants apparently unconcerned about, or simply unaware of, what they were building over.