Excavation

Date 7 August 2007 - 30 September 2007

Event ID 558263

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/558263

ND 4542 8688 Excavation continued this year from 7 August–30 September 2007 at the Cairns, Windwick Bay,

South Ronaldsay, as part of on-going research investigating Orcadian souterrains and their contexts. The main open area trench, some 15 x 15m, was the main focus of work.

Massive roundhouse. Work continued in structure A, a massive roundhouse with a total diameter of c22m, an internal diameter of 11.3m and a wall thickness of over 5m. A quadrant was excavated on the SW part of the interior, revealing that the wall of the structure survives to a height of 1.5m and that an intact flag floor survives beneath the mass of rubble which appears to have been deliberately and rapidly introduced at the end of the

life of the building. Occupational material and midden deposits in the interior yielded several coarse stone tools and pottery fragments of possible early Iron Age date. Several internal othostatic partitions indicate a radial layout inside the building. The excavated quadrant also allowed the examination of the previously recorded gap in the masonry wall of structure A and this gap was confirmed as a mural chamber, a teardrop-shaped cell around 1.8m in maximum diameter. This cell contained many large pieces of unworked whalebone. Also present was a large quantity of charcoal including possible charred withies together with a large piece of whalebone embedded in the wall at the entrance to the cell. This may indicate a hurdle screen or doorway that burnt down. Scorching on the adjacent inner wall face of the roundhouse may be related to such an event. It now therefore appears that the main entrance to Structure A lies further to the SE.

While the surviving height of the wall is too low at 1.5m to preserve evidence of some architectural features, such as a scarcement ledge, the question of the exact nature of this roundhouse was nevertheless further elucidated by an examination of the wall-core material on the NE where the wall had been slighted in antiquity. This revealed that the wall had an internal makeup of clay, soil and rubble dumps, which may indicate that the roundhouse does not possess the classic hollow-walled architecture of a ‘true broch’. This information,

together with the overall proportion of the wall thickness to internal area (the so-called percentage wall base), shows that structure A may exhibit some but not all of the traits of brochs. It is therefore likely to be a complex Atlantic roundhouse similar to Crosskirk in Caithness, rather than a high broch tower. The apparent early date of finds from the interior of the structure may support this provisional interpretation.

Sunken feature/Souterrain. Work continued in the centre of the roundhouse, in structure D, a rectangular sunken chamber that was partly revealed in 2006. A substantial deposit of in situ blocking stones was removed from the junction of the putative entrance passage and the chamber on the W side of structure D.

This revealed a large, partly rubble-filled, and still roofed, voided space defined by two lines of upright stone side panels, apparently confirming that this is a passage lying to the W of the main subterranean chamber. The fact that the structure represented a distinct, roofed building in its own right demonstrates that it was not simply a later modification of the interior of structure A, as previously considered possible. Structure D was constructed by digging into the mass of rubble in the interior of structure A and lining the cut with large uprights capped by substantial flags that have partly subsided, with a thick clay cap on top. In the deliberate blocking material we found a fragment of a copper alloy object, probably an unusual brooch. Below and in alignment with the base of the wall face of the souterrain chamber was a row of uprights which were probably further elements of the structure A internal architecture. This appears to show that the souterrain was built with some awareness of the layout of the massive roundhouse, and it may be that the deliberate in filling of the roundhouse and the construction of the souterrain were close in time, or indeed part of the same event.

Later activity on top of the remains of the roundhouse. Work also continued on the areas of later activity in the NW of the main trench. Structure B is a very well laid out set of uprights forming a rectangular or oblong building dating to the early part of the Late Iron Age. Its domestic nature appears to have been confirmed with the excavation of a large central rectangular hearth and the presence of occupation deposits. Stratigraphically, the construction of structure B was shown to be later than the use, and probably the abandonment, of the nearby souterrain. A small extension to the N of the main trench adjacent to structure B revealed part of another set of similar uprights laid out in identical fashion but turned around 90 degrees. This seems to represent the southern part of another building similar to structure B. A flagged passageway complete with threshold sill and pivot stone, possibly connecting these two structures as well as affording access to an external yard, was used at one point as a shell midden. This therefore appears to be a well preserved settlement zone of later middle Iron Age and/or earlier Late Iron Age date, post-dating structure A

extending across the centre and the N of the mound.

Archive to be deposited with Orkney SMR and Orkney Museums.

Funder: Orkney Islands Council, Orkney Archaeological Trust, Glasgow University, Manchester University.