Beside a possible cashel in County Mayo, a set of earthen banks once defined a neat rectangular enclosure, roughly 37 metres by 18 metres, extending northward from the cashel's east and west ends. That cashel, a stone ringfort of early medieval type, was itself uncertain enough in character; but the banks attached to it raised further questions about whether the whole complex might represent something more unusual, something more Norman than Irish.

When Hubert Knox examined the site in 1911 and recorded his observations, the banks were already much reduced, resembling, in his words, common field banks. He nevertheless interpreted them as a possible bailey, the defended courtyard that typically accompanied a motte, a raised earthen mound used as a fortification base by Norman settlers from the late eleventh century onwards. His suggestion was that the cashel itself might be a small motte, which would recast the entire site as a Norman adaptation of an older Irish form, or perhaps a Norman construction built to resemble one. It is a compelling reading, though the evidence was never conclusive. What Knox recorded has since disappeared entirely. The slight undulations visible to the north-west of the cashel today hint at some kind of earlier ground use, a field division or cultivation plot perhaps, but the interpretation remains uncertain. Straight field walls, now swallowed by overgrowth, run roughly north to south and define the edges of a modern rectilinear field far larger than anything Knox described. The eastern boundary of that modern field clips the outer edge of the cashel platform itself, confirming that it was laid down after the cashel had already fallen into disuse and partial ruin.