EHG1373 - Trial trenching - A830 Upgrading: Loch nan Uamh to Arisaig, Lochaber

A programme of archaeological trial trenching and test pitting was undertaken by CFA Archaeology Ltd (CFA) between June and July 2005. These took place within the corridor of the proposed A830 Fort William to Mallaig Trunk Road upgrading, between Loch Nan Uamh in the south-east and Arisaig in the north-west. Significant sites at Arisaig, Borrodale and Lochan Torr na Nighinn (Brunary Burn) were evaluated, with additional work being undertaken at a number of other sites of less significance. At Borrodale, to the east of the burn, trenching in this area was restricted by an access track to Burnside Cottage, inaccessible steep slopes and an overhead power line. The latter prevented the evaluation of a level area of grassland. Four trenches were excavated (1-4). The area contained three shallow features with similar charcoal-rich fills, the charcoal often appearing vitrified. Artefacts recovered from them included several unabraded shards of post-medieval glass from one feature and two masses of corroded iron from a second. It was recommended that any further features in this area be identified and recorded during topsoil monitoring. The area available for trenching to the west of the Borrodale Burn was less than anticipated due the presence of a foul sewer (not shown on the service maps supplied), a water pipe, areas of steep ground and isolated trees. A private water supply leading to Borrodale House shown on the service maps near to Trench 11 was in fact located to the east of the burn. Ten trenches were excavated. Two limited areas contained pockets of buried soils, from which prehistoric artefacts were recovered. A series of features sealed beneath the buried soil may be the remnants of prehistoric activities of uncertain character. It was considered that this area had the potential to contain important archaeological evidence relating to earlier prehistoric activity, possibly a settlement. The buried soils, and in particular the buried turf-line / OGS, had the potential to contain palaeoenvironmental information. It was recommended that this area be subject to further excavation. Trial trenching in the area of ES Site 51 comprised 142m². The placement of trenches was restricted by the presence of overhead power lines, trees, exposed bedrock and a foul sewer. Six trenches were excavated which were initially partially placed to investigate a linear field bank and most of the available level ground. Only Trench 16 located any archaeological remains and these consisted of what appeared to be a burnt mound. It was recommended that the burnt mound and adjacent and subjacent features would be fully investigated. At Brunary Burn, the site of a two buildings (Structures 'A' and 'B') and associated features (Site 61) were subject to trenching (Trench A within Structure A and Trench B within Structure 'B') and a linear transect of five test-pits (0.5m by 0.5m) was excavated in the angle between Structures A and B, parallel to the former. Based on the results it was recommended that the remains of this settlement be subject to further excavation to provide further information on the dates, functions, and inter-relationships of the various features identified by survey and sample excavation; and to further investigate the historical, social and economic context of the settlement. A trial trench at Site 66, a small enclosure, revealed that this structure appeared to be a modern animal shelter or treatment area and all the finds would be consistent with such an explanation. No further mitigation measures were recommended. An additional trial trench at Site 67, a possible structure or clearancecairn revealed that this site appeared to be the result of recent machine clearance of fluvial debris from below the adjacent Beasdale Road Bridge. No further mitigation measures were recommended. Test pitting was also undertaken at Beasdale along the road corridor within the gently sloping and lightly wooded area to the east of the mouth of the Beasdale Burn. This area lay at between 5m and 12.5m OD and was the most attractive for former activity due both to its more level and sheltered nature and to the nearby presence of the Beasdale Burn. In the event no evidence was found for lithic production or use. No clearly or probably worked lithic remains were found and there was no charcoal content in any deposits. No further mitigation measures were recommended. <1> NOTE: the site of the test pits at Beasdale and the trenches at Site 66 and 67 are not shown on any plan in the report. Open excavation was subsequently undertaken by CFA Archaeology at several of the sites - see EHG2944, EHG3369, EHG3370. As a follow up to the 2005 work, a monitored topsoil strip was carried out in July and August 2007, targeted on areas that had previously been shown to be of archaeological sensitivity - see EHG3371, EHG3372, EHG3373 and EHG3374. The excavation assemblage from the overall project is listed in the NMS catalogue under Acc. No. 2012.11. <2>