At Desert, that spread of burnt material marks a fulacht fia, a type of prehistoric cooking or processing site found in extraordinary numbers across Ireland, and particularly concentrated in Munster. The typical form involves a horseshoe-shaped mound of shattered stone beside a trough, where water was heated by dropping fire-heated rocks into it. The stones, once used and quenched, crack and become useless, and so the mound of discarded fragments slowly builds up over repeated use. What survives at Desert is that accumulated debris, exposed where the plough has cut across it.

What makes the location quietly notable is not the single site but the pairing. A second fulacht fia lies approximately 150 metres to the north-east, which points to either sustained activity in this area over time or perhaps contemporaneous use of two nearby sites. Ireland has thousands of recorded fulachtaí fia, most of them dating broadly to the Bronze Age, though some span into the Iron Age. Their precise function has long been debated; cooking is the most widely accepted explanation, but proposals ranging from textile processing to bathing have all found scholarly support at various points. At Desert, the evidence is reduced to what a ploughed field has offered up, which is enough to confirm the site but leaves the finer questions open.