Located 1.75 kilometres south-southeast of Site A, this structure was identified as a cruciform passage tomb, one of Ireland’s distinctive Neolithic burial monuments. Before its unfortunate destruction, archaeologist Seán Ó Nualláin documented the site in 1983, recording five standing stones and several displaced slabs that hinted at the tomb’s original grandeur.

The tomb’s layout revealed the sophisticated architectural knowledge of its builders. At its southwestern end lay a terminal chamber, formed by two imposing orthostats; large, carefully matched stone slabs that created a space measuring one metre wide and at least 2.5 metres long. Perpendicular to this main chamber, a smaller side chamber extended southward, marked by what appeared to be a low sill stone at its entrance and a taller stone at its rear, creating a compact space just 0.8 metres in length. A fifth stone, positioned low to the ground where the passage would have met these chambers, likely served as another sill stone, marking the threshold between the entrance way and the sacred burial spaces beyond.

Though this monument has been lost to time and development, its memory persists through archaeological records and surveys. The site was first noted in historical documents by Fagan between 1845 and 1848, and later included in various archaeological inventories including the Sites and Monuments Record and the Record of Monuments and Places. Its destruction represents one of many losses to Ireland’s prehistoric heritage, yet the detailed recordings made before its demolition ensure that future generations can still learn about the burial practices and architectural skills of the Neolithic communities who once inhabited this corner of Donegal.