The opening of the horseshoe, some three and a half metres wide, faces south-east, and a small low mound sits within that opening. It is an unremarkable-looking feature in the landscape, easily mistaken for a natural rise in the ground, which is precisely what makes it so quietly extraordinary.

This is a fulacht fia, a type of prehistoric cooking site found in enormous numbers across Ireland, particularly in low-lying areas near water. The general interpretation is that such sites were used for boiling water by heating stones in a fire and dropping them into a water-filled trough; the repeated heating and fracturing of the stones produced the characteristic mounds of dark, crumbly burnt material that survive today. They date broadly to the Bronze Age, though some examples are earlier or later. What makes the Knockatooan site particularly interesting is that a second fulacht fia lies only four metres to the south-south-east, suggesting that this stretch of slope above the stream valley was used repeatedly, or perhaps simultaneously, for whatever activity these monuments represent. The proximity of two such sites to each other is not unique in Ireland, but it is far from commonplace, and it raises questions about scale of use and the organisation of activity in this small patch of north Cork.