The dry stonework is built of large, irregular stone blocks from the immediate vicinity.
The oval chamber measures 10.8 to 9.8 metres, is paved and has a large fire spot in the middle.
In the south-west of the chamber a short aisle branches off to the right and leads to an unusually well-preserved staircase in the wall.
The side walls of the stairs slope inwards, which indicates that it was originally designed as a cantilever vault.
Finds included saddle and rotary querns, a potential stone 'lamp' and several sherds of coarse pottery.