This one asks you to look at nothing at all. In the townland of Ellistronbeg, in County Mayo, a rectangular earthwork once sat in level pasture, substantial enough to be mapped by the Ordnance Survey in 1929, and now gone entirely, levelled to the point where no surface traces survive. The ground holds no mound, no ditch, no shadow of a bank. What you are standing in front of, if you go, is an absence.

The 1929 Ordnance Survey record is the last firm documentation of what the earthwork looked like from above. Rectangular enclosures of this kind are a broad category in Irish archaeology, encompassing everything from early medieval farmsteads to ecclesiastical enclosures, the shape alone offering little certainty about function or date. What the record makes clear is that by the time the landscape was being systematically surveyed for archaeological purposes, the feature had already been removed, its form preserved only in the earlier cartographic record. D. Lavelle's 1994 survey of Ballinrobe and district, which took in the areas around Lough Mask and Lough Carra, catalogued it among the archaeology of the region, noting its former presence and its current erasure in the same breath.