Lewis, Carnan A' Ghrodhair

NB 51163 63969 (Canmore ID: 4425) Carnan a’ Ghrodhair Souterrain was discovered in c1941 by military personnel during their construction of a WW2 lookout post. The souterrain remained accessible until the late 1950s, when it was blocked with soil and modern rubbish. This detritus was partially excavated over two weeks, 19–30 June 2017, in order to assess the condition and integrity of the structure, with the intention to improve its condition through conservation, and allow access to the monument in the long-term. After the spoil was excavated from the interior of the WW2 lookout post, and part of the souterrain passage, the following was discovered:

Access to the souterrain passage is gained via a rectilinear hole in the concrete floor of the lookout post, which was presumably covered over by a wooden or metal hatch while in use, to prevent those on duty from stumbling into the hole. The hole has been partially widened through erosion, with a broken edge evident at the SE and SW edges, it measures 0.58 x 0.68 x 0.94 x 1.1m.

A concrete lintel (900 x 170mm), now cracked and weakened, forms the top of the entrance to the souterrain passage, below the NE wall of the lookout post. This lintel is supported by three bricks on the right hand side (SE), and four bricks on the left hand side (NW), which appear to have very little supporting them save the scant remains of part of the souterrain passage walls, most of which are now missing from under the brick supports, although they appear on the NE side of the lintel and brick support entrance.

The walls and roof of the passageway immediately beyond the concrete lintel, to the NE of the lookout post, are poorly constructed and have failed in several places. It is assumed that this walling and roof have been reconstructed at some point, presumably at the time of the building of the lookout post. Only the very top levels of the passage walls, c0.8m below the roof lintels, were revealed by excavation, given the deteriorated state of the walls and roof of the passage. The walling to the left (NW) has slumped into and onto the spoil which fills the passage, therefore any further excavation of the passage would compromise the souterrain structure. At least two lintels have also cracked, and several roof stones are hanging into the passage. No further excavation proceeded, the souterrain passage and WW2 lookout post were photographed and drawn, and backfilled with spoil. A range of artefacts were recovered including several sherds of local, handmade pottery, including three decorated sherds, and at least three rim sherds.

Archive: NRHE (intended). Report: NRHE and Commun Eachdraidh Nis

Funder: Historic Environment Scotland

Chris Barrowman – Comunn Eachdraidh Nis

(Source: DES, Volume 18)

NB 51163 63969 (NB56SW 1) Carnan a’ Ghrodhair souterrain

was discovered by military personnel during construction

of a WW2 lookout post. The souterrain, running to the NE,

consists of a dome-shaped chamber c2.5m in diameter and

1.5m high and is reached by a c3–4m long passageway.

Above ground, apart from the remains of the modern lookout

post, there is only a slight mound to indicate its location.

Ground penetrating radar (GPR) surveys were undertaken,

11–12 June 2018, over a 50 x 50m area centred on the known

extents of the souterrain.

A wealth of anomalies have been recorded. However, many

of these are likely to be due to past agricultural activity,

natural variations in the subsoil and rabbit activity.

The data suggests that the souterrain extends c10m to the

SW of the lookout post. The response from the NE extension

of the souterrain is less clear. While there is clearly some

evidence for the structure in the data, and an anomaly

consistent with the chamber has been detected, it is not very

coherent. However, this may be due to variations in the fill of

the structure resulting in different levels of contrast.

Well defined linear anomalies have been detected to the

NE of the souterrain. These are on the same alignment as the

souterrain and may be of archaeological interest.

Several additional curvilinear responses have been recorded

throughout the survey area, which may be significant and

could indicate the remnants of structures. However, they

could simply be due to rabbit burrows.

Archive: Rose Geophysical Consultants

Funder: Comunn Eachdraidh Nis

Susan Ovenden – Rose Geophysical Consultants

(Source: DES Volume 19)