These horizontal mills, sometimes called Norse mills or tide mills in popular usage, were among the earliest mechanised grain-processing structures in Ireland, powered by water channelled through a trough to strike blades on a wheel lying flat beneath the millstone, without the gearing required by a vertical wheel. Their simplicity made them common across early medieval Ireland, and their timber components almost never survive. The Bealad find was therefore an unusual one.

What the reclamation work exposed was a wooden penstock, essentially a boxed wooden channel or sluice used to direct and accelerate water flow onto the mill wheel, measuring 3.5 metres in length and up to 0.7 metres wide. It was rebated along both sides, suggesting it had once been fitted with a lid to control or contain the flow. The splayed end, where water would have exited at speed, had suffered some damage during the drainage work itself. Alongside the penstock lay an irregularly shaped wooden plank, roughly 1.3 metres long, with three evenly spaced bores towards one end; its precise function is not recorded, but such components are consistent with the working machinery of a small horizontal mill. At the edge of the nearby stream, a patch of ground was found to be covered in cobbles laid in a deliberate pattern, likely the remnant of a hardstanding or working surface associated with the mill's operation. The site lies in the southern portion of an irregularly shaped field, in boggy pasture to the east of the stream.