Excavation

Date 20 August 2016 - 3 September 2016

Event ID 1023512

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/1023512

NR 21045 56420 (NR25NW 3) A two week long excavation and geophysical survey of the chambered cairn of Slochd Measach (Giant’s Grave) was carried out, 20 August – 3 September 2016, by a team from the University of Reading and Bournemouth University.

Slochd Measach chambered cairn is located in the forestry plantation on the SE slopes of Beinn Tart a’ Mhill near the southern tip of the Rhinns of Islay (NR 21045 56420). The work was undertaken with scheduled monument consent and section 42 consent granted by Historic Environment Scotland. This was a second fieldwork season at the site

following the evaluation and survey in 2015 (DES 2015, 42).

Two out of four planned trenches were excavated in 2016 (Trenches 1 and 3). Trench 1 was oriented SW/NE and positioned along the front two compartments of the chamber (C1 and C2) and the adjacent area at the NW side of the cairn. It measured 5 x 4m with a smaller 2.5 x 1m

extension to the SW overlapping with the outer face of the third compartment C3. The excavation in Trench 1 revealed the presence of toppled façade stones lying in the peat in the NE part of the trench and the scant remains of a possible semi-circular shelter constructed against the outer side of the orthostats. Underlying the peat the entire area of the

trench, including the interior of the chamber compartments C1 and C2, was filled with rubble. The top rubble deposits were loose and in places overlying rubble mixed with peaty soil. More compact rubble representing undisturbed cairn material followed, increasing in size with the depth. The

initial stages of the cairn were built from stacked upright stone slabs wedged with smaller rubble on top of thin soil horizon, which survived in places, but was mangled in others under the weight of the construction.

One of the aims in Trench 1 was to investigate the kink in the alignment of the chamber visible in plan between the back compartments C3 and C4 and the front compartments C1 and C2. Excavation of the cairn material confirmed that the apparent misalignment was caused purely by the

toppling of the othostats of compartments C1 and C2, rather than a separate construction phase. The cairn in this area was built as a single phase of construction, abutting the in situ orthostats and following the movement of those that toppled. Toppled and leaning orthostats of compartments C1 and C2 prevented the excavation inside these compartments except for the very front of compartment C1, which was

much disturbed. The base of compartment C1 consisted of natural bedrock and glacial till. Trench 3 measured 5 x 2m and was E/W oriented. It

was positioned over a concentration of high resistance anomalies in the immediate area of an outlier stone visible c10m SSW from the back end of the chamber. The excavation revealed an unexpected structural sequence

consisting of a substantial wall built from stone boulders and incorporating the outlier stone, which was moved into this position from elsewhere on the site, most likely the chamber or the façade of the chambered cairn. The wall was N/S oriented, but it is not entirely clear how far it continues beyond the limits of the trench. The electrical resistance survey, conducted over the entire forestry clearing, suggests that it could continue S for another 20m and beyond the limits of the survey. The wall was overlying a stone platform or an area of hard standing built from medium sized cobbles, which covered the entire area of the trench, thus extending to either side of the overlying wall and beyond the limits of the excavation. To the E it was picked up in 2015 in test pit (TP11) located 4m from

Trench 3, but its overall limits remain undetermined. The electrical resistance survey shows a complex suite of high resistance anomalies to the E and the SE of Trench 3, but they are difficult to relate to the stone platform in the trench without further excavation. Underlying this platform or area of hard standing was a tumble of larger stones, which might represent disturbed cairn material of the chambered cairn. Below this tumble was a well-constructed level platform built from large stone slabs and kerbed to the SE by a double line of long rectangular stone slabs running diagonally across the trench on the same orientation as the

chamber of the chambered cairn. This was postulated to be the kerb of the chambered cairn, judging by the size of its construction, the alignment and the stratigraphic position towards the base of the sequence and on top of a thin soil horizon overlying glacial till.

A systematic environmental sampling strategy was employed throughout the stratigraphic sequence in both trenches, providing a suite of potential C14 dates to be added to those already obtained in 2015. A 3D photogrammetry survey of the monument was also conducted. The excavation will continue in 2017 with the opening of Trenches 2 and 4.

Archive: Museum of Islay Life, Port Charlotte. Report: HES and WoSAS

Funder: University of Reading

Darko Maricevic and Steven Mithen – University of Reading

(Source: DES, Volume 17)