Excavation

Date 29 July 2017 - 19 August 2017

Event ID 1038953

Category Recording

Type Excavation

Permalink http://canmore.org.uk/event/1038953

NR 21045 56420 (NR25NW 3) A three week fieldwork season was carried out, 29 July – 19 August 2017, at the chambered cairn of Slochd Measach (Giant’s Grave). This was the third and final fieldwork season at the site following work in 2015 and 2016 (DES 2015, 42; 2016, 32–33). The work was undertaken with scheduled monument consent from HES, and consisted of an excavation, an electrical resistance tomography survey,

continued photogrammetry of the architecture of the cairn and a terrestrial 3D laser scan survey.

The excavation continued with the opening of three trenches. Trench 2 was opened in the forecourt and Trench 4 targeted the previously unconfirmed SE end of the façade (see plan in DES 2016, 33). Furthermore, Trench 4 was positioned in reference to the outlier megalith and a possible

round cairn that was postulated from the results of the electrical resistance survey. Trench 5 was placed c20m to the S in order to investigate a suite of high resistance anomalies in this area.

Trench 2 was the continuation of Trench 1, excavated in 2016, and it measured 5 x 6m. In Trench 1 we investigated surviving remains of the heavily robbed cairn and its relationship with the chamber and identified one possible displaced façade monolith. This was an elongated pinkish

cyenatic gneiss rock (S32), a type of stone that was also used for the front jamb stones at the entrance to the chamber. The chamber was otherwise made entirely of massive greenish metagabbro megaliths. The SW end of Trench 2 continued to investigate the line of largely missing façade, which now has only one remaining standing monolith at the NW end.

The rest of the trench projected into the forecourt area where a long thin mattagabro monolith S23 lay prone on the surface of the peat. This monolith must have been moved or toppled relatively recently considering our dates from the base of the peat indicate that its formation falls within

the last three hundred years (DES 2015, 42). The sequence below the peat consisted of a series of rubble deposits, which were underlying monolith S23, but in turn overlying another massive, but much broader, metagabbro stone S33. The position of S33 suggests that it formed part of the façade and that it toppled forward onto a thin soil horizon, which was directly above natural glacial till. Thus, it appears that the dismantlement/collapse of the façade and the portal stones happened in stages and probably over a prolonged period of time. The rubble at the front of the entrance abutted displaced megalith S19, which we previously interpreted as a probable

capstone, but which could have equally been another façade stone, considering its similarity to S33. Either way, it is likely that S19 was placed across the entrance into the chamber as a deliberate blocking, pushing portal stone S20 forward in the process. Distinctive metagabbro-rich green rubble deposit abutted S19 in its new position and it may have been a deliberate blocking deposit, as its extent was limited to the entrance area. The rest of the trench was covered by more extensive rubble deposits containing many regular flat slabs that once probably formed dry wall panels between the monoliths, as part of a ‘post and panel’ built façade.

In Trench 4, another displaced metagabbro megalith (S36) was partially covered by the peat at the top of the stratigraphic sequence and partly overlying a large flat cyenatic gneiss block (S35). The rest of the trench was covered by dense rubble, which was also partly overlying stone S35. The excavation of the uppermost rubble defined underlying structures, the latest of which was a roughly built cist at the W end of the trench. This appears to have been formed by the rearranging of some of the underlying

cairn rubble into a sub-rectangular structure of which only the SE corner had well defined sides made from set on edge stones. The interior was lined with smaller stones forming an oval space in which a pot (SF17) was placed. The pot was on its side with the base against the stone lining of the cist. No human remains, burnt or otherwise, have been found around it. It is doubtful that the oval space, which was 0.5m in length and 0.3m in width, could have contained an adult inhumation. The pot was lifted together with its contents, excavated in the lab and is being professionally conserved. The SE end of the cist was overlying a wall, which was by its alignment and construction interpreted as the continuation of the kerb wall of the chambered cairn, first identified in 2016 in Trench 3. The kerb wall ran up to

flat slab S35 and abutted it neatly, which suggests that they were either part of the same construction or that S35 was a reused part of some earlier structure. Two further features were excavated at either side of the kerb wall. While the outer face of the kerb was lined with thin flat stones set on their side, the interior was occupied by continuous rubble in which several large stones were set upright around loose rubble fill. Our interpretation of this feature is that it represents the stone socket for the missing end façade stone and, thus, the main objective of Trench 4 to locate the meeting point of the kerb wall and the façade of the chambered cairn has been met. The combined evidence from Trenches 2 and 4 and the upstanding architecture of the chamber suggest that the façade was slightly concave rather than a straight one as previously believed. On the

outer side of the kerb, a later rubble deposit was abutting its face. Below this layer a small semi-circular niche was constructed, abutting the kerb. It contained the tightly packed remains of two ceramic vessels (SF25, SF27).

Although formal analysis of the pottery is yet to take place, the initial assessment suggests that both the cist pot (SF17) and the niche vessels (SF25, SF27) belong to the Bronze Age phase of activity on the site. At the E end of the trench the upper rubble deposits were abutting flat stone S35, but underlying them was a coarser rubble or a stone-built structure, which was underlying stone S35. This deposit had a curved eastern edge with the remains of a possible kerb. This was the earliest structure in the trench

and considering it was predating the construction of the kerb of the Clyde-type cairn, it can only be a preparatory platform for its construction or the remains of an earlier smaller round cairn. The limits of the trench did not allow investigation of the full extent of this structure.

Trench 5 revealed a much simpler stratigraphic sequence. The source of the high resistance in this area was a layer of rubble below the peat, which probably represents a tumble down the slope of the cairn material. The rubble was overlying a layer of buried soil in which a leaf-shaped arrowhead (SF15) was found.

Archive and report: NRHE and WoSAS

Funder: University of Reading, Society of Antiquaries of Scotland and Islay Heritage

Darko Maricevic and Steven Mithen – University of Reading

(Source: DES, Volume 18)