Croft 119, Clachtoll, Assynt, Sutherland Erection of House, Formation of Access and Installation of Services Ref No. SU-09-012 A
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Croft 119, Clachtoll, Assynt, Sutherland Erection of house, formation of access and installation of services Ref no. SU-09-012 Archaeological Watching Brief and Trial Trenching Catherine Dagg for Helen Theakston and Graham Acreman 5 Bayview Terrace Lochinver By Lairg Sutherland IV27 4LB Croft 119, Clachtoll, Assynt, Sutherland: Erection of house, formation of access and installation of services.Ref no. SU-09-012 Archaeological Watching Brief and Trial Trenching Location Plan 2 Croft 119, Clachtoll, Assynt, Sutherland: Erection of house, formation of access and installation of services. Ref no. SU-09-012 Archaeological Watching Brief and Trial Trenching Site summary Rural site 204062 926865 Site location (NGR) Total area of construction Work required a. Archaeological watching brief b. 5% trial trenching Area of investigation required a. Access road b. House footprint, hardstanding 1.0 Summary Trial trenching of the proposed house site and hardstanding concluded that there were no buried archaeological features within this area. A Watching brief on ground breaking work for the access road recorded late 19th century middens associated with the original croft house, and contemporary land drains 2.0 Background This archaeological evaluation has been produced in response to a brief from Highland Council Archaeology Unit for a second phase of evaluation of the proposed development. An initial desk-based evaluation and walk-over survey of the area of ground to be affected by the development, carried out on 2.7.09, located a number of visible, minor and previously unrecorded archaeological sites, and concluded that there is high potential within the development area for features of Prehistoric or Mediaeval settlement and land use to be buried under a deep deposit of windblown sand. 3.0 Archaeological Background Although there are several important archaeological sites in the Clachtoll area, including the nationally important broch and a burnt mound, both dating to the Iron Age, there are no recorded sites within and only one adjacent to the development area: 3 • A’Clach Thuill: vitrified wall at NC 0380 2670 Her Ref: MHG 43508 This small area of vitrification is located on the NW corner of the prominent landward section of the split rock on the headland west of the development area. While no actual walling is evident, this site is ideally located to be defensive. Vitrification of rock can occur in other contexts involving high temperatures, such as inside kilns and on smelting sites and it is possible that the site was chosen to utilise strong winds to produce the high temperatures required for industrial processes. It is, however, more likely that this is a small defensive site as suggested by G.Sleight during his research into the distribution of Iron Age defensive sites around the Assynt coast. Eroding midden deposits on the rock adjacent to the vitrification have produced charcoal, burnt bone and one small fragment of possible Iron Age pottery. While Clachtoll Broch is the more impressive monument, its location within the bay is not ideally suited to see and be seen up and down the coastline. The split rock does command extensive views to north and south and may have served the purpose of defence for the local community before the site proved too small for development into a broch. This begs the question as to the location of domestic settlement within the prehistoric period. The almost complete lack of contemporary settlement types, notably hut circles, within Assynt, has led to the present hypothesis that, in a landscape of limited arable ground, settlements have not shifted over time and the remains of prehistoric settlement are most likely to lie under later, Early Modern townships or be concealed in some other way. It can be expected that the domestic settlement associated with a defensive site on the split rock would be relatively close. It may be significant that the township name Clachtoll or Balclachinhole as recorded by Roy in the 1750s links the township to the split rock Clach Thuill although it is not now the closest topographical feature. The township is known to have drifted slightly in its location during the early modern period and this is a process which could have continued from earlier times. 4.0 Results of Initial Archaeological Survey Of the 17 features identified within the area surveyed on 2.7.09, six can securely be dated to the modern period. These are the croft buildings, sites 1-5 and site 15, the dyke known to have been built after 1878. A further seven sites may date to the establishment of the croft in the 1850s or 1870s, when tenants moved from elsewhere on the estate would have brought with them relatively archaic methods of using the land and building techniques. These seven, sites 6-12, are features of land and stock management and some are recorded on the 1878 map. However, they could also be remnants of a pre-crofting landscape. Sites 16 and 17, areas of rigs and field clearance cairns are typical cultivation features of the pre-crofting, or Early Modern period. While an end date to this period can be given by known historical events, with some leeway for the conservatism of the tenants, it is less easy to give an earliest date in a period when farming techniques barely changed for centuries. In fact, 4 similar dykes to site 12, located in the vicinity of Clachtoll Broch, are locally thought to be prehistoric land boundaries. Sites 13 and 14, boundary dykes which do not appear on early mapping and which are partially or almost totally concealed by sand, may be associated with a much earlier phase of settlement The proximity to the defensive site on the split rock and the extensive areas of rigs on the headland suggest that the early settlement of Clachtoll may have been much further south than as recorded in the 18th century. It is also possible that the nucleated township of the 18th century was preceded by a more scattered settlement pattern of individual farmsteads, one of which being located close to the later croft house site. Similarities may be drawn with the Loch Borralie area of Durness, where features of settlement from the Iron Age onwards are now being revealed by eroding sand. However, the lack of obvious fresh water may equally have prevented such settlement at Clachtoll. The depth of deposit of windblown sand means that any early settlement features will be preserved on an old ground surface and will only be revealed by removal of the sand. 5.0 Recommendations of Initial Evaluation The following recommendations for further archaeological work were made in the initial evaluation: House site The house site is located in an area where no archaeological features were noted, although it is very close to site 12, dyke. The sand at this location is of an unknown depth and it is considered likely that it will conceal features of early settlement and land use. Site 13, wall, which is almost completely buried, is heading directly towards the house site. Recommendations: Trial trenching or a watching brief during ground breaking work and excavation of foundation trenches will allow any buried archaeological features to be identified and recorded. There is the possibility that these features may prove to be significant and may require more detailed excavation than can be carried out during a watching brief. 2Access Road upgrade. Construction of the road will damage site 12, dyke. This is probably the only site which will be directly affected as, although the road passes close to the building group, it is unlikely to damage them. Ground breaking for the road will be relatively superficial and is unlikely to penetrate to the base of the layer of windblown sand. Recommendations: A watching brief during ground breaking work may be advisable along the section of road running south of the croft building complex. 5 This will allow the dyke, site 12, to be investigated and possibly dated and will allow the identification and recording of any sites exposed during work where the sand layer is more shallow. 6.0 House Site: 5% Trial Trenching Trench 1. NC 04085 26800 – NC 04062 26802 (Photos 1-4) This was laid out along the long axis of the development, approximately NW-SE and 24m in length. The following stratigraphy was noted: Point a. 1. Topsoil, pale brown sandy 200mm 1m from SE end of trench 2. Sand, windblown but no apparent layering 450mm 3. Grey sand-clay mix 150mm 4. Rock (Lewisian Gneiss) in clay matrix Total depth to rock: 800mm Point b. 1. Topsoil 400mm 4m from SE end of trench 2. Windblown sand 400mm 3. Pink-brown sand-clay mix 80mm 4. Grey sand-clay 100mm 5. Grey clay subsoil, dense and compacted Total depth to clay: 980mm Point c. 1. Topsoil 250mm 8m from SE end of trench 2. Dark sand-topsoil mix 270mm 3. Windblown sand 840mm 4. Pale, yellow sand 190mm 5. Pink, compacted clay subsoil containing degraded rock: 150mm 6. Bedrock Total depth to bedrock: 1700mm At this point it was felt that the health and safety issues associated with following the bedrock deeper were too great, so the trench was continued only at this depth. No changes in the sand were observed and the bedrock did not rise. It appeared most likely that the original pre- windblown sand ground surface observed the deep cleft visible at both shorelines. The following archaeological observations can be made about Trench 1. • No archaeological features, deposits or artefacts were noted in the trench • No former ground surface in the form of soil horizons appeared to exist between the clay subsoil and the windblown sand • No layering of the sand was visible, suggesting either the sand was laid down during one major event or there was not time between events for vegetation to establish or soils to form.