Excavations at Black Loch, 2018
Our understanding of the nature and development of the settlement at Black Loch has continued to expand and evolve with every season of excavation there. During the last 2 seasons, in 2017 and most recently in May/June of 2018 work has focused in the southern half of the settlement, where we have explored more of the defensive perimeter and several more structures. In parallel with the fieldwork we are undertaking a post-excavation programme, the results of which are providing us with a detailed chronological framework for the settlement, as well as insights into the living conditions within the houses, and the kind of activities that took place there. With more samples and finds from both seasons yet to analyse this summary of our current understanding is still very much a work in progress but here is what we think…..
Based on the current stratigraphic and chronological evidence we now think there were at least three major episodes of building activity on the island. Episode 1 consisted of a settlement of three roundhouses, ST1, ST2 and ST5 clustered in the northern half of the island around the end of a log trackway which was aligned on the causeway off the island. This settlement was protected by a palisade of closely set alder logs around its southern perimeter. During the 2018 season we investigated the junction between the trackway and the palisade and uncovered a very impressive structure. At the point at which they meet there was a distinct threshold, consisting of a massive oak beam, with a jamb cut into it against which a gate or doors could swing shut. The beam had been notched at either end to fit around the oak posts which secured it in place.
Structure 2 was the best preserved of the roundhouses and displayed evidence for sophisticated design and construction, with an impressive entrance way flanked by a façade of oak planks which formed the outer wall of the house. Once inside the house the visitor would have been further impressed by the massive square stone hearth which lay at the centre of the house. The floors of the house consisted of thick layers of rushes, sedges and bracken laid over sub-floors of brushwood; they were frequently resurfaced, removing the dirty floor coverings and replacing them with fresh material. One of the key insights that has emerged from the analytical work on these floor deposits (this includes soil micromorphology, artefact, macroplant and insect analyses, and faecal steroids) is that cleanliness was very important to the occupants!
Possibly as a consequence of this cleanliness we have found very little artefactual material associated with this phase. This changed this year with the discovery of midden deposits lying outside the palisade and to one side of the trackway. As well as the more mundane finds of shell and unburnt animal bone we found a beautifully decorated wooden bowl, squashed but mainly intact, a crucible fragment and a complete saddle quern.
The chronological evidence places this episode in the latter half of the 5th century BC. Dendrochronological analysis of the oak timbers from Structure 2 indicates that they were felled in 435 BC and Bayesian analysis of radiocarbon dates from the hearth and floor deposits suggests that the house was not occupied for more than 30 to 40 years so it had probably been abandoned by circa 400 BC. Tree-ring analysis of alder, ash and hazel wood indicates that Structures 1 and 2 were built in the same year.
Episodes 2 and 3 are currently dated by radiocarbon alone and both occurred sometime in the 4th to 3rd centuries BC. In Episode 2, settlement expanded out into the southern half of the island, with the construction of a new defensive perimeter, a palisade of closely-set oak planks. We have been able to trace this palisade on either side of the entrance onto the island but it may not have completely encircled the settlement. The trackway, which seems to have been the main thoroughfare of the settlement throughout its occupation, continued through the palisade to the natural causeway joining the island to the shore. The trackway had been resurfaced many times but major modifications were probably made in Episode 2, when a threshold beam of oak, exactly like across the Episode 1 boundary, was installed, with brushwood surfaces on either side.
Structures 3 and 6 were built just inside the palisade and are probably associated with the Episode 2 settlement. Structure 3, which was excavated this year, is a roundhouse but it is smaller and more insubstantial than the roundhouses of Episode 1, with walls and a post-ring of slender stakes. There are other significant differences which suggest that Structure 3 may have been a workshop rather than a domestic habitation. Firstly, there is a stratified sequence of 7 hearths, each of varying construction which migrate around the centre of the structure, and each separated by a new floor. Secondly, the floors are dirty! Pockets of fly pupae were frequently observed and unburnt animal bone was found scattered about. Perhaps most importantly, the structure was relatively rich in artefacts including lumps of slag, a complete crucible as well as crucible fragments, caches of coarse stone tools and worked bone artefacts. One of the most intriguing finds from this year’s excavation, a finely made baton-shaped wooden object, was found within the floor deposits of this structure. Lying against the outer wall of Structure 3 was an extensive and deep deposit of unburnt hazelnut shells. We are speculating that the structure may have been a workshop associated with metalworking, weaving or food processing.
Structure 6 may also have been a workshop like Structure 3. It consisted of two clay oven-like structures with stone bases built over wickerwork floors and although we didn’t locate any evidence for an outer wall (probably because of the size of the trenches) the construction of the floors and the insect fauna found within them suggests that they lay within a covered building. So there may have been a series of workshops around the perimeter of the site during Episode 2.
The only other structure that has been investigated is Structure 4, another roundhouse which may also be part of the Episode 2 activity. It lay over the Episode 1 palisade and displays all the characteristics of the other roundhouses, a large stone-built central hearth and wickerwork floors which were replaced several times. Again, we have scant evidence for the superstructure, no walls or post-ring.
Finally, in Episode 3 an earthen rampart and post-built palisade were constructed over these structures. Our only evidence for this episode comes from the defensive perimeter and the structures around the entrance onto the island, which become increasingly elaborate. The rampart and palisade were built on a slightly different alignment to, and extended out over the previous entrance structure, and a post-lined bank extended out from the rampart along the side of the trackway, in effect corralling any visitors to the settlement along the trackway.
This year we will be analysing the soils, timbers, ecofacts and artefacts from the 2017 season. One of the key objectives will be to define the chronology of Episodes 2 and 3, to determine whether there was continuous occupation of the site or whether there were periods of abandonment. And parts of our chronological model outlined above may change……