Description from RCAHMS 1978;
This souterrain lies on the crest of a low ridge 168m NNW of Wester Yardhouses farmhouse and under the foundations of a modern field wall. The passage has recently been deliberately blocked 4.6m from the entrance and the outer section reconstructed.
Excavations in 1923 (A Fairbairn 1924) revealed that from the entrance, which faced E, the passage ran westwards for 2.0m, then NNW for a distance of 2.7m, and finally W again for a further 7.2m. The width of the passage varied from 0.9m to 1.7m. The walls were corbelled and rose to a height of 1.5m at the point where they were spanned by the only surviving lintel-stone. In the two outer sections of the passage the basal course was formed by particularly massive stones, the largest measuring 1.9m in length and 0.4m in depth, but in the innermost section the lowest course consisted of large flagstones set on edge. The entrance was flanked by two portal stones, and another pair stood at the junction of the central and innermost sections of the passage. At the W end, where the souterrain was at its widest, traces of burning were found on the clay floor. The finds, which are in the National Museum of Antiquities of Scotland (NMAS), comprised chert and flint flakes, several scraps of hand-made pottery of indeterminate date, a block of ‘red pigment’ and fragments of medieval pottery.
Flint arrowheads have been picked up locally, and one perfect barbed and tanged specimen was found close to the entrance some years ago.