Connagill, Strath Halladale, Sutherland

Trial Pit and Bore Hole Excavations

Archaeological Monitoring

Catherine Dagg

For

ASH 21, Gordon Street Glasgow G1 3PL

Connagill, Strath Halladale, Sutherland: Trial Pit and Bore Hole Excavations

Archaeological Monitoring

Site Name Connagill, Strath Halladale, Sutherland Location NC 90595 59816 Site Type Multi-period settlement and field system Project Preliminary site works: trial pits and bore hole excavations Work required Archaeological monitoring Client ASH, 21 Gordon Street, Glasgow G1 3PL

1.0 Executive Summary

Archaeological monitoring of the mechanical excavation of 27 trial pits and 12 boreholes, aimed at ascertaining the nature and depth of underlying glacial deposits and geological strata, noted no archaeological deposits or features, but noted the nature, depth and extent of improved soils associated with prehistoric cultivation.

2.0 Aims

A new electricity substation is proposed at Connagill, Strath Halladale, adjacent to Tower 33 on the Dounreay – Beauly 275Kv overhead transmission line.

A programme of excavation of test pits and boreholes was required in advance of the finalising of the plan and location of the substation and submission for planning consent. These excavations are located along the proposed access road and across the substation construction area, and consist of:  Trial pits measuring approximately 2.5-3m by 0.6-0.7m

 Boreholes measuring approximately 0.30m by 0.30m to a maximum of 0.50m by 0.5m

3.0Archaeological Work

3.1 Marking of archaeological exclusion zones

In advance of any plant being brought on site or any ground breaking work, the archaeologist identified and marked out exclusion zones around all visible archaeological features, using high visibility tape, and explained the system to the site crew. Sites were sketched and location recorded using GPS as a precaution, and to both compare with previous survey results and inform the Environmental Statement on the proposed substation site. A gazetteer of minor archaeological features is given in Appendix 1.

3.2 Protection of Features

Plant was directed to avoid all marked archaeological features, to approach the site through the extant gap in the head dyke and to cast spoil away from adjacent archaeological features. Where avoiding crossing of linear features was impractical, a route was agreed and speed kept to the minimum to reduce the dislodging of stones.

3.3 Ground-Breaking Work

All ground breaking work for each of the test pits was monitored by the archaeologist until a depth was reached which was considered to be natural deposit. After this stage, excavation work was allowed to continue unmonitored. Hand digging of boreholes was not directly monitored, but each location was checked and recorded.

The trial pits were excavated by mechanical digger at locations decided by the drilling contractor, although after advice from the archaeologist on avoidance of archaeological features. Boreholes were partially excavated by hand using spade and shovel to a depth where the drill could be inserted.

4.0 Site Description

The area of the proposed sub station is a level terrace south of the Connagill Burn. A narrow, intermediate terrace occupies a slightly lower level to the north and west, after which the ground falls steeply to the burn and to the strath of the Halladale River. To the east the ground rises sharply with exposed rock faces.

Vegetation cover varies from good grassland on the west slope falling to the Halladale River and covering the north and west part of the main terrace, to almost vegetation-free stony ground on the intermediate terrace to the north, and wet, mossy peat to the south and east. Rushes have colonised much of the terrace.

The site is crossed by a modern access track, which forks at the centre of the terrace, the north track giving access to a water treatment plant on the hill, and the south track added recently to give access to the Dounreay-Beauly OHL, which passes to the east of the terrace. There are also modern, mechanically excavated drainage ditches, draining westwards. Low mossy mounds scattered across the southern part of the terrace were probed and proved to have no stone content; these are probable peat stack bases

The archaeological site, Connagill farmstead, is located on the steep west-facing slope to the west of the sub station site. One long house and attached enclosure survive, but two further buildings recorded on the 1st edition OS map have now been completely removed and at their location is a substantial quarry scoop. It is assumed that the stone of the buildings was removed during construction of retaining walls at the edge of the public road and that the quarry was opened at the same time. A further scoop into the hillside appears to be the robbed remains of a corn kiln. These features all lie to the north of the present access track, on the relatively steep but stepped slope from the road to the terrace.

5.0 Summary of findings of trial pit monitoring.

A total of 27 trial pits were excavated over four days. One day was lost due to access issues, so the original goal of 42 trial pits was not reached, but the pits were distributed across the whole site. Only five pits were not located on the main terrace: pits C01, C02 and C04 were located on the slope to the west of the terrace and C03 and C06 were located to the north, on an intermediate terrace (C03) and on ground sloping gently to the Connagill Burn.

The only feature of archaeological interest was the depth of soil, indicative of improvement for cultivation or grazing. Of the 27 pits, 14 contained no soil, six contained a thin mineral soil layer less than 100mm, and 7 contained soil deeper than 100mm. These 7, pits C01, C02, C05, C14, C19, C20 and C27, were located either on the west and north of the terrace, adjacent to field clearance mounds and banks, or on the grassy west slope adjacent to Connagil farmstead remains. The soil was richest, a black loam, at the base of slope near the road, but deepest at the west edge of the terrace, at pit C19 with a depth of 250mm. Much of the soil was poor, sandy and gritty with noticeable quartz inclusions.

In two pits, substantial soil deposits were overlain by peat: pit C02 with 150mm of peat covering 120mm of soil, and C27, with 80mm of peat overlying 120mm of soil. Pit C02 is located on the intermediate terrace between the main terrace and the west slope, while pit C27 is located SW of centre of the main terrace and some distance from field clearance piles. The other five pits with soil depths measuring 100mm or more had no peat cover, but five pits with soils measuring up to 100mm in depth , pits C03, C11, C16, C17 and C21, had a cover of peat measuring up to 260mm. The fourteen pits containing no soil contained peat measuring between 150mm and 600mm in depth, lying directly on the gravel subsoil.

Fig.2 Soil depths and peat cover

6.0 Conclusions

Results of monitoring of test pitting suggest that while the broad terrace which is the proposed location of the substation does not contain any archaeological remains of habitation dating to either the prehistoric or to more recent settlement which terminated with the clearances, the more favoured and drained area of the terrace was improved for cultivation or grazing. This area covers the north edge of the terrace, approximately 300m E-W and 150m N-S where soils have built up to a maximum depth of 200mm. Subsequent to this phase of land use, some of the margins of this area was covered with peat, to a maximum depth of 240mm, while the central part has persisted as grassland to the present day.

Habitation during the prehistoric period is represented by two hut circles, both located to the west of the terrace, on well-drained locations overlooking the strath. Later habitation, in the form of the post- mediaeval farmstead of Connagill, also occupied the western slope and the construction of a head dyke cutting off the terrace from the farmstead suggests that in the post-mediaeval period, this area was no more than hill grazing for the farmstead.

7.0 Recommendations

Siting of the electricity substation on this terrace will remove all archaeological features identified on the upper terrace above Connagill, but should not impact on the township features or on the two hut circles to the west. Further archaeological investigation may be advisable to clarify the nature and function of the minor features and to retrieve dateable and environmental samples.

Catherine Dagg 12.2.13

Appendix 1. Gazetteer of archaeological features

Field Clearance mounds.

The following eight mounds had the appearance of typical bronze-iron age field clearance piles. Mostly circular, although some were more linear, and covered in moss with few stones visible, these are mostly distributed at the north edge of, and on the north west part of, the main terrace.

 NC 90693 59814  NC 90616 59811  NC 90614 59798  NC 90617 59796  NC 90634 59811  NC 90638 59817  NC 90634 59823  NC 90672 59822

Other possible features

 Small ring of stones at NC 90608 59790 A setting of medium-sized stones, forming a ring of approximately 1.5m in diameter

 Area of rubble NC 90589 59790 A scatter of medium-sized stones covering an area approximately 2m by 1m

 Small ring of stones on slope NC 90535 59818 A setting of medium-sized stones forming a ring of approximately 1.5m in diameter

 Linear feature, rubble bank 90544 59814 to 90544 59789 Low, moss covered rubble bank spread to 500mm but to a height of no more than 300mm

 Linear feature, rubble bank 90534 59774 to 90525 59765 Low, moss covered rubble bank spread to 500mm but to a height of no more than 300mm

 Possible hut circle at 90504 59846 Located immediately to the east of the north east corner of the farmstead enclosure, on the west edge of a narrow intermediate terrace between the main terrace and the slope west to the and described as a small road, are circular banks of what appears to be a hut circle of similar dimensions to the one located by CFA (CFA5) An entranceway to the south is extended by further banks.

Hut Circle between enclosure and proposed access road (foreground)

Previously Recorded Features

Long dyke, corners at 90537 59858 Linear feature, recorded on modern mapping although not shown on the 1st edition OS map. Recorded by CFA (CFA6) Medium to large stones and earth form a more or less continuous bank which runs just below the main terrace, turning east to run along the south bank of the Connagill Burn. No visible contemporary features of the cleared farmstead are located east of this, so it is effectively the head dyke

Building at 90516 59794 Square footings of a small building, as recorded on modern mapping although not shown on the 1st edition OS map. Recorded by CFA (CFA7) and described as a small bothy or shieling hut, although not typically either. Three sides of the square setting, north, east and south, are formed by low turf and rubble banks, but the fourth, west, is closed by three large stones. This suggests the structure was open to the west, possibly closed as required. No parallels are obvious.

Appendix 2: Trial Pits

Monitoring of work was carried out by Catherine Dagg (pits 1-11) and Nick Lindsay (pits 12-27)

Date: 9.12.12 Weather: Dry, clear and sunny

Trial Pit No C01 GPS Co-ords NC 90428 59784 Location immediately south of access track close to junction with road Topography west-facing slope Vegetation Grass Drainage Good Adjacent Archaeology Farmstead features to north, hut circle to south, both over 20m Stratigraphy Peaty improved black soil 200mm Sandy intermediate soil-subsoil mix 250mm Compacted sandy gravel subsoil

Trial Pit No C02 GPS Co-ords NC 90489 59816 on narrow intermediate terrace on west-facing slope dropping from Location main terrace to the road Topography Level Vegetation Grass Drainage Good Adjacent Archaeology SE corner of farmstead enclosure Stratigraphy Peat 150mm Soil 120mm Gravel subsoil

Trial Pit No C03 GPS Co-ords NC 90570 59856 intermediate terrace to north of main level area. Dropping north Location towards Connagill Burn, but within enclosing dyke Topography Level Vegetation poor and sparse, mosses and patches of heather Drainage Poor Adjacent Archaeology None Stratigraphy Peat 80mm Minerally soil with quartz inclusions 50mm Intermediate soil-subsoil with gravel Orange-brown gravel subsoil with embedded glacial boulders

Trial Pit No C04 GPS Co-ords NC 90524 59834 Location Intermediate terrace to west of main terrace Topography Level Vegetation poor, deer grass Drainage Poor Adjacent Archaeology Possible hut circle within 10m Stratigraphy Wet rooty peat 200mm Gravel subsoil

Date: 11.12.12 Weather: Generally dry and clear with some snow flurries

Trial Pit No C05 GPS Co-ords NC 90595 59816 at northern edge of main terrace, with ground falling away to Connagill Location Burn to the north. Topography Level Vegetation cropped grass Drainage Good Adjacent Archaeology 5m from field clearance mound Stratigraphy: Compacted dry peaty soil 150mm Soil, compacted, mineral rich with large quartz inclusions 40mm Subsoil, brown, sandy and stony

Trial Pit No C06 GPS Co-ords NC 90648 59833 Location North of main terrace towards Connagill Burn Topography Gentle slope, scattered pools and boulders Vegetation Poor grass, moss and rushes Drainage Poor Adjacent Archaeology None Stratigraphy: Peat, rooty, 150mm Brown sandy stony subsoil

Trial Pit No C07 GPS Co-ords NC 90712 59790 Eastern part of main terrace, just north of water treatment works access Location track Topography Level, with pools and boulders Vegetation Grass, moss and rushes Drainage Poor Adjacent Archaeology None Stratigraphy: Peat of variable depth to a maximum of 400mm Lenses of mineral soil with quartz inclusions to a maximum of 25mm Uneven surface of subsoil with embedded boulders

Trial Pit No C08 GPS Co-ords NC 90705 59754 Location Eastern part of main terrace south of pylon access track Topography Level, with boulders Vegetation Grass, moss Drainage Poor Adjacent Archaeology Stratigraphy: Root mass of vegetation 50mm Peat 40mm Mineral soil 20mm Brown stony subsoil

Trial Pit No C09 GPS Co-ords NC 90758 59765 Location At east edge of main terrace just north of pylon access gate Topography Level, with scattered boulders Vegetation Grass, moss, rushes Drainage Good Adjacent Archaeology Stratigraphy: Peat, undulating base to a maximum depth of 300mm Gritty decayed stone interface 10mm Brown sandy subsoil

Trial Pit No C10 GPS Co-ords NC 90701 59725 Location South east part of terrace, 50m north of pylon access gate Topography Level Vegetation Moss, sphagnum, deer grass Drainage Poor Adjacent Archaeology None Stratigraphy: Rooty fibrous peat 280mm Dense, dark homogenous peat 100mm Subsoil, fine grey clay with boulders

Trial Pit No C11 GPS Co-ords NC 90692 59649 Location South corner of site Topography Level Vegetation Moss, deer grass, rushes Drainage Poor Adjacent Archaeology None Stratigraphy: Peat 120mm Degraded stone interface 30mm Subsoil, cream-brown sand with cobbles and boulders

Date 12th December, 2012 Weather Sleety, grey skies.

Trial Pit No C012 GPS Co-ords 290663 959634 Time 12.40 Orientation 0980 Location 80m W of E boundary fence Topography Level Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology None nearby Depth of peat 350mm Depth of soil None No soil. 200mm rooted peat turf, overlying 150mm rich dark peat, Description overlying brown sands and gravels.

Trial Pit No C013 GPS Co-ords 290519 959690 Time 14.20 Orientation 0780 Location 40m N of old wooden fence & 60m S of new access track Topography Gently sloping down to W Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology 15m SE of marked clearance cairn Depth of peat 200mm Depth of soil None Description No soil. Rooted peat turf, overlying brown sand.

Trial Pit No C014 GPS Co-ords 290542 959745 Time 14.50 Orientation 0080 Location 2m S of new access track Topography Gently sloping down to W Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology 30m W of burnt mound Depth of peat None Depth of soil 150mm No peat. Rooted sandy brown topsoil, overlying brown sands and Description gravels.

Date 13th December, 2012 Weather -100, sunny, clear, frosty.

Trial Pit No C015 GPS Co-ords 290637 959649 Time 10.25 Orientation 0560 Location 100m W of E boundary fence & pylon line & 80m S of access track Topography Very gently sloping down to W Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology None nearby Depth of peat 300mm Depth of soil None Description No soil. Rooted peat, overlying brown sand, gravel and boulders.

Trial Pit No C016 GPS Co-ords 290621 959723 Time 10.40 Orientation 0980 Location 15m S of new access track Topography Level, but just to N of slight rise Vegetation Rashes, with grass Drainage Well drained Adjacent Archaeology None nearby Depth of peat 260mm Depth of soil 60mm Rooted peat with boulders, overlying brown sandy soil, overlying Description brown sands and gravels.

Trial Pit No C017 GPS Co-ords 290603 959757 Time 10.50 Orientation 1010 Location In the ‘V’ where the access track splits Topography Level Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology None nearby Depth of peat 200mm Depth of soil 40mm Rooted peat, overlying white-speckled peaty soil, overlying brown Description sands and gravels.

Trial Pit No C018 GPS Co-ords 290551 959767 Time 11.10 Orientation 0840 Location 15m N of access track & 25m S of truncated telegraph pole Topography Very gently sloping down to W, above break of slope Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology None nearby Depth of peat 150mm Depth of soil None Description No soil. Rooted peat turf, overlying brown sands and gravels.

Trial Pit No C019 GPS Co-ords 290526 959779 Time 11.30 Orientation 0840 Location 20m N of access track & 50m W of truncated telegraph pole Topography Sloping down to W Vegetation Mainly grass, with occasional rashes Drainage Very well drained Adjacent Archaeology 15m SE of marked square feature attached to boundary wall Depth of peat None Depth of soil 250mm 100mm rooted soil, overlying 150mm good dark brown sandy soil, Description overlying brown sands and gravels.

Trial Pit No C020 GPS Co-ords 290630 959803 Time 11.50 Orientation 0040 Location 40m N of access track Topography Raised area, shelving down to burn to N Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology Marked clearance cairns 15m to W, 15m to SW & 10m to NE Depth of peat None Depth of soil 200mm 100mm rooted light brown soil, overlying 100mm darker brown sandy Description soil, overlying brown sands and gravels.

Trial Pit No C021 GPS Co-ords 290663 959824 Time 13.30 Orientation 0020 50m S of small valley, 60m N of access track, 100m W of E boundary Location fence Topography Gently sloping down to N Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology 10m W & 20m E of marked clearance cairns Depth of peat 240mm Depth of soil 80mm Rooted peat, overlying black peaty soil with white flecks, overlying Description brown sands and gravels.

Trial Pit No C022 GPS Co-ords 290750 959818 Time 13.45 Orientation 0350 Location 40m W of E boundary fence, 50m N of access track, 30m S of burn Topography Gently sloping down to NW Vegetation Mainly rashes with some grass Drainage Boggy Adjacent Archaeology 10m S of marked clearance cairn Depth of peat 400mm Depth of soil None No soil. 200mm rooted peat turf, overlying 200mm rich dark peat, Description overlying brown sands and gravels. Trial Pit No C023 GPS Co-ords 290749 959712 Time 14.00 Orientation 0160 Location 10m W of E boundary fence, between 2 gates Topography Gently undulating Vegetation Grass Drainage Well drained Adjacent Archaeology None nearby Depth of peat 550mm Depth of soil None No soil. 150mm rooted peat turf, overlying 400mm rich dark peat with Description boulders, overlying brown sands and gravels.

Trial Pit No C024 GPS Co-ords 290686 959665 Time 14.20 Orientation 1080 Location 60m W of E boundary fence, 50m S of S access track branch Topography Gently sloping down to W Vegetation Rashes, with grass Drainage Well drained Adjacent Archaeology None nearby Depth of peat 200mm Depth of soil None No soil. 100mm rooted peat turf, overlying 150mm rich dark peat, Description overlying brown sands and gravels.

Trial Pit No C025 GPS Co-ords 290659 959664 Time 14.30 Orientation 1120 Location 90m W of E boundary fence, 90m S of access track Topography Level Vegetation Rashes, with grass Drainage Well drained Adjacent Archaeology 40m NE of 2 marked clearance cairns Depth of peat 300mm Depth of soil None No soil. 100mm rooted peat turf, overlying 180mm dark peat, Description overlying 20mm rich black peat, overlying brown sands and gravels.

Trial Pit No C026 GPS Co-ords 290625 959679 Time 14.40 Orientation 1200 Location 40m S of S access track branch Topography Gently sloping down to W Vegetation Grass, with rashes Drainage Well drained Adjacent Archaeology 30m N of 2 marked clearance cairns Depth of peat 600mm Depth of soil None No soil. 100mm rooted sandy peat turf, overlying 500mm rich dark Description peat, overlying brown sands and gravels.

Trial Pit No C027 GPS Co-ords 290590 959718 Time 14.55 Orientation 1670 Location 30m S of access track Topography Sloping down to W Vegetation Rashes, with grass Drainage Well drained Adjacent Archaeology 30m S of marked burnt mound Depth of peat 80mm Depth of soil 120mm Rooted dark sandy peat turf, overlying smooth fine-grained peaty soil, Description overlying brown sands and gravels.

Borehole Co-ordinates

Borehole No Easting Northing 1 290400 959820 2 290463 959793 3 290617 959743 4 290671 959794 5 290694 959679 6 290674 959647 7 290614 959718 8 290698 959740 9 290711 959781 10 290667 959805 11 290578 959790 12 290572 959750