By 1907, the same spot had been reduced on the revised edition to a vague smudge of rough ground. What the mapmakers were recording, without quite knowing it, was something far older than any ringfort: a Neolithic court cairn, a type of megalithic monument in which a stone-lined forecourt opened onto one or more burial chambers, used by farming communities thousands of years before the maps existed.

The cairn at Lemgare sits on a gentle south-to-north spur in an otherwise low-lying landscape. It is subrectangular in shape, measuring roughly 24 metres northwest to southeast and 18 metres northeast to southwest, and is now heavily overgrown. At its southeastern end, a broad open court, about 6.5 metres wide and 5 metres deep, survives with reasonable clarity. Two portal stones mark the entrance from that court into a small chamber beyond, though the chamber itself is in poor condition, measuring only around 1.7 metres in length and just over a metre wide. A noticeable hollow in the body of the cairn behind this point suggests that further chambers once existed and were systematically robbed of their stonework at some point, leaving only a depression where structure used to be.

The 1834 misidentification as a fort is easy to understand. Without excavation, a weathered and overgrown cairn can look like any number of things, and the slight elevation of the spur would have looked, to a surveyor's eye, like a deliberately chosen defensive position. Court cairns were in fact deliberately sited in the landscape, though not for defence; the forecourt arrangement is thought to have served a ceremonial function, possibly related to communal burial rites. At Lemgare, enough survives, the portal stones, the court outline, the telling hollow, to piece together what was once a considerably more elaborate structure.