Monument record 2072 - ALLT CHRISAL, BARRA

NL69NW 7.38 6425 9770

During the initial survey of 1988, T25 was recorded as being an outbuilding of a possible farmstead centred upon the blackhose NL69NW 7.06. The facade, raised platform and and the central channel were clearly observed in the initial survey and form a distinctive set of characteristics that set the building apart from the normal black house type. The site was directly in the line of the new link road to the Vatersay causeway and the building was therefore excavated in 1990.
Under a mask of post-abandonment material, T25 was revealed as a round-cornered rectangular building with external measurements of 7.6m N-S by 5.6m transversely. The structure was bult against a large boulder which had been incorporated into its S outer wall. The surviving walls stand to an almost uniforn meight of 0.8m, and are on average 1.2m wide. Like most of the farmstead buildings, they are constructed with only a single course of large orthostat boulders set to form an inner and outer wall with an earth-filled cavity between them. In the W outer wall, however, several courses of smaller boulders were built up from the stream bed as a revetment against the slope. These continued up the slope to become an integral part of the upper building. The entrance to the building would most likely have been in the S part of the E wall or the SE corner, but the whole of this area was destroyed by animal burrowing.
The interior is divided into two parts by a wall of vertically-placed monolithic boulders which butt against the inside of the E and W outer walls. This wall retains a a raised platform or floor (0.6m high) which fills the N portion of the interior area. The facade of the wall is pierced by a central opening which leads to a narrow stone-lined flue passage that bisects the platform. Before the flue passage reaches the rear wall of the building it widens into a circular shape terminus.
The construction sequence of the platforms and flue passage begins with large beach pebbles being stacked around the outer edges of the room in a packing of beach sand and gravel. As the work progressed, revetment walls on either side of the gap were built to form a narrow flue passage leading from the entrance gap in the facade. the infilling was finished with layers of compacted stony earth topped with a compact sandy soil to form the surface of a raised floor on either side of the flue passage. In the S half of the room, a thin compacted layer of sand and small stones had been laid as a rough floor.
There were no deposits or artifacts to indicate the function of the building. There was no evidence, as one would expect in a domestic context, of a method for heating the building or of using fire in an industrial manner. There was an absence of hearths in any form and, apart from the insubstantial patches of burnt peat ash in the upper layers, there was no evidence of charcoal, burnt stones or other fire-associated deposits. The compacted floor showed no evidence of churning or mixing, as would be expected if farm animals had been housed inside the structure.
Pottery finds were sparse, comprising a few late-18th to early-19th century fragments, several of which matched those found in NL69NW 7.06. There were also few residual sherds of prehistoric pottery and struck flints, but no prehistoric features were found. Little of the pre-building ground surface was observed, the floor ebing left undisturbed.
The functional purpose of this building remains unresolved, although it is almost certainly part of the farm complex centred upon the blackhouse NL69NW 7.06. The morphology of the building would suggest a large drying or curing oven, with flue and raised floors. The lack of evidence for the prolonged use of fire, while not discounting this possibility, does leave an element of doubt. Until other examples of this form of building can be found and excavated, this interpretation must remain speculative.
The road was subsequently realigned to the S of this building, in order to preserve it.
P Foster 1989; K Branigan and P Foster 1995; NMRS, MSS. 595/3 and 595/6.

NL 6426 9770
The kiln barn T25 sites on the east bank of Allt Chrisal, not on the west bank as shown on the SMR map (now moved MML 8.2.07).
Knott 2001, 11

P Foster, 1989, Discovery and Excavation, Scotland, 69 (Bibliographic reference). SWE10416.

K. Brannigan & P. Foster, 1995, Barra: archaeological research on Ben Tangaval from the end of the Ice Age to the Crofting Commissio, 35, 37, 49-51, 62-3, 100-15, 117-19, 120-3, 131, 136-7 figs. 4.1 and 4.8-4.10 (Bibliographic reference). SWE33223.

Carol Knott, 2001, Barra & Vatersay Survey, Western Isles (Unpublished document). SWE41119.