A classic broch tower is a cooling-tower-shaped drystone-built structure, unique to Scotland, and iconic of that nation’s Iron Age. Over 200 of the roughly 700 brochs in Scotland are to be found in Caithness, which in consequence has the highest regional concentration of brochs. In the popular imagination, however, brochs remain most commonly associated with the Hebrides, Orkney and Shetland. The broch at Mousa, Shetland, is the tallest at 13m, and is certainly the most famous. Relatively few brochs in mainland Scotland have been excavated in recent years. In Caithness, however, community groups have begun to excavate examples of these impressive and complex sites. This will begin to redress the geographical bias and expand the information base, helping to shed light on the people who built, rebuilt, used and reused them.
Nybster Broch is located on a dramatic coastal promontory just north of Wick. The broch and its surrounding complex of structures were excavated in the late 19th century by local landowner Sir Francis Tress Barry. Few records remain beyond paintings by John Nicolson and photographs taken by Tress Barry, who was a pioneer in the use of photographic recording on archaeological sites. Tress Barry was interested in uncovering the layout of the buildings, which he achieved by exposing and trenching along the structures’ wallfaces. The excavation of sites previously dug by antiquarian enthusiasts is often unnerving, as one never really knows the full extent of those previous forays; at both Nybster and Thrumster (Broch, excavated in July 2011 by Yarrows Heritage Trust with AOC), however, untouched archaeological deposits were present in no short supply. An upside to the antiquarian interventions is that archaeological deposits are encountered virtually just beneath the modern turf.
Previous investigations at the broch at Nybster in the summer of 2005 had shown that the massively thick (8m) walls were solidly built, with no evidence of cells, galleries or stairs; in strict classification, this places it in the simple Atlantic roundhouse category according to Armit (1991) and MacKie (2007). The roundhouse is curious in its design, with such huge walls and a relatively small interior space (just 5m in diameter); the massive effort required to build such unusually thick walls seems incongruous with the volume of interior space achieved. The implication is that the structure attained a considerable height and had multiple floors, but this is impossible to demonstrate conclusively from the surviving remains.
As previous work had focussed on the broch at Nybster, this season’s fieldwork investigated some of the surrounding structures. The community’s excavations began by exploring the large rampart enclosing the broch and outbuildings on the promontory. Work there has shown that the defences originated with the construction of a stone-faced wall across the neck of the promontory. This primary structure, just 2.5m wide, was incorporated within a more substantial defensive rampart about 5m thick, set behind a deep rock-cut ditch. During this phase, the original entrance through the rampart was dismantled and rebuilt to incorporate a cell within the thickness of the rampart. This feature is redolent of the Clickhimin blockhouse on Shetland or that at Head of Scatness, Shetland, previously excavated by AOC. The cell had a paved floor and was accessed from within the enclosed promontory by a short flight of stairs reaching the wallhead, from which one stepped down into the room. A saddle quernstone had been built into the wall of the cell, perhaps considered too worn for purpose and reused as building material. A narrow passage defined by vertically set slabs was formed behind the rampart, and if enclosed, would have sealed off the flight of steps, at the bottom of which a pivot stone was discovered.
The rampart’s extent, construction and collapse were explored further by the excavation of a second trench, this one near the southern edge of the promontory. This exposed a section of the rampart face, sitting on bedrock, and deposits of stone collapsed from higher in the rampart were clearly visible in section. Nowhere was the enormity of the rampart builders’ gruelling task more palpable than here, with quarried bedrock and massive stone blocks exposed for the first time since prehistory.
Following the rampart’s collapse, cists (stone-lined boxes) were dug into its remains. As at other Caithness sites, these cists may be late Pictish or Viking burials dug into the ruinous remains of the broch complex; had these cists contained bone, it is unlikely that it could have survived in the prevailing conditions. The cut of the deepest cist descended through the secondary rampart until it reached the wallhead of the primary rampart. At this point, digging moved eastwards, descending sharply so that the primary rampart formed the western side of the cist. An ovoid pendant made of serpentine was discovered in the fill associated with this phase of activity. It is easy to imagine it falling unnoticed from around someone’s neck as they concentrated on digging the cist.
A second phase of excavations focussed on the cellular buildings situated close to the easterly point of the promontory. Buildings of this type are often believed to be evidence of Pictish re-use of Iron Age broch sites. We wanted to learn more about one of the largest cellular buildings (OB4), and two smaller buildings to the north (OB2E) and northwest (OB2W). The inner wallfaces of OB4 were visible thanks to Tress Barry’s work in the 1890s, so de-turfing was sufficient to reveal the basic structure of the building. Work then continued to investigate the remaining floor surfaces, revealing various paved surfaces and a number of hearths.
Some of the hearths show evidence of numerous phases of use, and will hopefully provide good dating evidence. A hearth in the form of a stone slab surrounded by a circle of end-set ovoid beach pebbles was revealed in OB2W. It seems as though Barry discovered the latter hearth during his excavations but left it in situ, continuing to excavate around it. The largest of the hearths, three-sided and rectangular with two probable pot-rest stones, was recorded by Tress Barry while others were not, although some had much taller orthostats. That any of these hearths was not noted by Tress Barry emphasises the potential for gaps in the records left for posterity by antiquarians (where any records were left at all), and reinforces the need for the multiple forms of recording employed in today’s archaeological excavations.
OB4 has two cells, one at the north-east end and the other at the south-west end of the ovoid building. The paving in these cells, as well as some massive paving slabs in the southern end of the building, was lifted in the hope that we would find dateable material in the sealed deposits beneath. We were successful on both counts, with a worked whalebone object being discovered beneath the paving in the southern cell, and small sherds of bone beneath the massive slabs in the interior of the main building.
A stack of slabs, collapsed at an angle into OB2E, concealed a context rich in archaeological material. Multiple layers of burnt material and the presence of many animal and fish bones suggest that this context was a middening deposit. Finds included numerous stone tools and pot sherds, a strike-a-light, two pot lids and a fragment of a Roman glass melon bead. This context lay above a layer of heat-damaged slabs, and was partially contained by an arc of stones, beneath which were further layers of burnt material.
The unearthing of numerous hearths and a strike-a-light in the midden deposit at Nybster give a sense of life to the broch complex. These discoveries make it easier for us to imagine that these imposing, cold, grey, dry-stone structures were home to living, breathing families, people who made jewellery and decorated their pottery. We should not patronise the broch builders by being surprised by these aesthetically pleasing finds; rather we should relish the chance to depict a more colourful image of their lives.
Ancient sites excavated and altered by antiquarian enthusiasts have long been considered unworthy of re-excavation. Thrumster and Nybster Brochs have provided ample evidence to refute this view. We should view these relatively recent phases of activity as another chapter in an ancient monument’s story, one just as worthy of archaeologists’ attention.
There is a pleasing parallel in the communal effort that must have been employed in building, reusing and maintaining these impressive sites, and in the community’s excavation of them many centuries later. We have barely begun to investigate Caithness’ brochs. Over three thousand person hours have been volunteered to this end so far; perhaps with a few thousand more we may begin to understand these enigmatic sites and those who lived, worked and died there.
Nybster Broch Project generously funded by Highland LEADER+, Heritage Lottery Fund and Highland Council.