Road construction has an awkward habit of destroying the past, but occasionally it turns up something unexpected before the tarmac goes down. At Kilrathmurry in County Kildare, the building of the M4 Kinnegad-Kilcock motorway did exactly that, prompting an excavation in 2004 that exposed traces of early metalworking activity in a borrow-pit, the type of excavated hollow from which soil and aggregate material is extracted during road construction.

What the excavation revealed, under licence number 04E1181, was modest in scale but significant in character: a spread of material associated with metalworking, the truncated remains of a bowl furnace, and part of what may have been a smithing hearth. A bowl furnace is among the simplest forms of smelting technology, essentially a shallow pit lined to contain burning fuel and ore, with air supplied to raise the temperature high enough to work metal. The fact that these features survived at all, even in a truncated state, suggests the site had once been a place where someone, at an unspecified point in the past, was doing the careful and skilled work of processing or shaping metal. The notes do not record a date for the activity itself, so its precise period remains open.