Look more closely at its south-western face and the structure begins to make sense: a wide arched recess, roughly two metres tall and nearly two and a half metres across, opens into a lower inner arch, and two horizontal ledges run across the front wall, one at mid-height of the recess and one just above the arch. This is a lime kiln, a structure once as ordinary to the Irish rural landscape as a ditch or a drystone wall, and yet one that most people today pass without recognition.

Lime kilns were the industrial workhorses of pre-modern agriculture. Limestone was packed into the kiln with fuel, burned at high temperatures, and the resulting quicklime was spread across fields to reduce soil acidity, or slaked with water and used as mortar and whitewash in building. The Tullig kiln is rectangular in plan, with a front wall approximately seven metres wide, and its arched draw-hole at the base allowed workers to rake out the processed lime once the burn was complete. The ledges visible on the front wall likely served a structural or loading function during operation. The kiln appears on the Ordnance Survey six-inch map of 1842, placing it firmly within the era of improving landlordism and agricultural intensification that characterised early nineteenth-century Ireland, when lime was in high demand across Cork's farmland and small-scale kilns like this one were built to serve local needs.