It is easy to miss, easy to dismiss as a natural feature of the ground, but the material beneath the grass tells a different story: burnt stone, heat-shattered and discarded in quantities that built up, over repeated use, into a mound roughly ten metres long and a metre high.

This is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, most dating from the Bronze Age. The standard interpretation is that stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, after which meat could be cooked. The broken, fire-cracked stones were raked out and piled to the sides of the trough, and it is those accumulated dumps that form the characteristic horseshoe shape seen here at Glanrastel. The mound measures 9.8 metres north to south and 5.7 metres east to west, with an opening 4.3 metres wide facing west, where the trough would once have sat. Burnt material is visible at the tip of the north-west arm, and a boulder marks the end of the south-west arm. The site's position on the south bank of a stream is entirely typical: reliable water was essential to the whole operation, and fulachtaí fia are almost always found close to a water source.