Dun Mhairtein

NC86NE 1 8535 6635.

(NC 85356635) Dun Mhairtein (NR)

OS 6"map, Sutherland, 2nd ed., (1964)

Dun Mhairtein is a promontory fort with a 'blockhouse'- type forework, probably dating from the 1st century BC or slightly earlier, whose surviving internal arrange ment owes nothing to the broch or post-broch occupation which occurs on most other forework-type forts on the north mainland.

A precipitous cliff promontory about 27m high, curves parallel with the mainland, from which it is separated by a geo. The fortification cuts off the tail of the promontory, enclosing an area 22m by 24m which is over-looked by the higher cliff on the mainland side of the geo.

The main feature is a stone-revetted rampart 4.2m thick at the west end, 5m wide at the east and 1.2m to 1.8m high, pierced slightly east of centre by an entrance passage 1.02m. wide at the outer end and widening inwards. An upright slab, set at right angles two-thirds of the way along the passage, forms a doorcheck. The ends of the rampart fade away towards the cliff-edge, and in front of it the ground has been scooped back from either edge, leaving a causeway, 2.5m wide, in line with the entrance. On the west side only, a bank, apparently of loose material and unrevetted, intervenes between the rampart and the ditch. It is about 3.6m thick and is separated from the rampart by a gap of 3m. The ditch on this side descends to the brink in three broad steps. It is possible th/t the interior of the fort has been enclosed by a wall following the cliff-edge, as traces can be seen running north from each end of the rampart.

Within the fort and about 8.3m back from the rampart is a complex of structures forming a shapeless mound in which part of the interior of a rectilinear hut has been exposed quite recently, the visible portions being the SE wall, 2.74m long, and parts of the SW and NE walls. The rest of the interior is choked with debris. It is well-constructed of orthostats, 0.9m high, topped by fine dry-stone walling now preserved to a height of0.3m at the SW corner where the topmost courses oversail slightly, although this may be due to bulging. In the debris is a possible lintel 1.2m long and 0.25m square.

A deep depression 3m to the NW gives access to, and possibly represents the collapsed terminal chamber of, a souterrain which runs NE and downwards, following the ground slope for 10.7m, and emerging in the cliff-face where there is a slight ledge 1.2m below the cliff-edge.

Here the passage is 0.8m wide expanding to 1.1m in the depression on the SW. Although it is choked with debris to within 0.5m of the roof it is possible to see along the whole length of it. The roof is of heavy lintels on orthostats and dry-walling and is broken in 3m from the entrance, at which point there are many earthfast slabs.

Resurveyed at 1:2500 in 1972 and revised in 1977.

RCAHMS 1911, visited 1909; R G Lamb 1980; R J Mercer 1981; Visited by OS (W D J) 3 May 1960, (A A) 8 November 1972 and (J B) 6 June 1977.