What was once a wedge tomb, a type of megalithic burial chamber built in the late Neolithic and early Bronze Age, typically consisting of a roofed stone gallery that tapers from west to east, has collapsed, been buried under field clearance, and finally lost altogether. Yet its name persists. Marked on Ordnance Survey maps as far back as 1842, and again on the 1920 edition, it was labelled "Dermot and Grania's Bed", a designation attached to dozens of megalithic sites across Ireland, reflecting a folk tradition that linked ancient monuments to the legendary flight of Diarmuid and Gráinne, the eloping couple of Irish mythology who supposedly sheltered at a different stone each night.

When the antiquarians William Copeland Borlase and Thomas Johnson Westropp examined the remains in the late nineteenth century, the tomb had already fallen. Borlase, writing in 1897, described two sidestones, each three metres long, lying flat and broken in the middle, with the chamber's original standing height estimated at around 1.22 metres. Westropp, visiting shortly after, recorded the roof-slab in more detail: over three metres long, nearly two and a half metres wide at its western end and narrowing to just under two metres at the east, it lay across the northern sidestone. Two smaller endstones had also been found beneath the larger slabs, and their differing lengths led Westropp to conclude there had been the "usual eastward taper" characteristic of wedge tombs. Both men noted the tomb had been embedded in a cairn, though that cairn had already been removed by the time they arrived. A 1952 survey by Ruaidhrí de Valera and Seán Ó Nualláin found no trace of it whatsoever.

A field inspection in 1998 identified a trapezoidal area of roughly nine by seven metres that may mark the original site. One side is defined by a field wall; the others are low, grass-covered banks, barely twenty centimetres high. The interior is heaped with overgrown field-clearance rubble. It sits within a larger multiperiod field system, which suggests the land has been worked and reworked across many centuries, each phase gradually obscuring what came before. The 1840 Ordnance Survey Name Book called it a "stone altar", which may say more about how nineteenth-century recorders perceived such things than about any actual ritual function. The name on the map outlasted the stones beneath it.