Motorway widening schemes are not usually where archaeology gets interesting, but the N7 Naas Road project in County Kildare produced at least one genuinely puzzling find. During centre-line testing in 2003 on a north-west-facing slope at Kill Hill, archaeologists noticed an anomaly in the soil: a ribbon of burnt clay encircling an oval of redeposited natural subsoil, with occasional flecks of charcoal scattered through it. Unremarkable at a glance, but worth a closer look.

Full excavation revealed a shallow pit, only about 0.2 metres deep and roughly a metre long, cut into the natural subsoil and shaped something like a figure of eight, oriented north-west to south-east. The lining of red burnt clay, between 50 and 60 millimetres thick, ran along both the base and the sides of the cut, which is what had given the feature its distinctive ribbon-like appearance before the soil was opened up. The larger of the two interlocking ovals sat at the north-western end and had a more consistently concave base, suggesting it may have been the main chamber. At the opposite, south-eastern end, excavators found a small circular depression, roughly 35 centimetres across and 15 centimetres deep, tucked into the base of the cut. The leading interpretation is that this hollow served as a housing for a set of bellows, which would point towards a structure designed to sustain and direct heat, most likely a kiln of some kind. A kiln, in its simplest form, is a fired chamber used to process materials such as grain, metal, or pottery through sustained heat. What this particular example was processing, and when it was built and used, remains unresolved; no dating evidence was recovered that would place it within any period with confidence.