Lewis, Loch Langavat

This project aims to investigate a number of recent spectacular underwater discoveries from lochs in Lewis, Outer Hebrides. A programme of non-invasive geophysical (sidescan sonar, dual frequency single beam echosounder), drone and diver based survey was carried out between the 11th and 21st July 2016. Three lochs were chosen for study: Arnish, Bhorgastail (also known as Carloway) and Langabhat. The results from work at all three sites indicate that artificial islets were a feature of the landscape during the Neolithic.

NB 42301 30238 Geophysical, aerial and ground survey at Loch Arnish worked well, with excellent results from both the sidescan and echosounder systems allowing for the loch to be mapped. The extent of the rubble foundations can be seen and plotted, as too can the variable depth of the loch and associated sediments. The crannog is clearly multi-period, with Neolithic and later pottery recovered by Chris Murray (in previous years), and later modifications (iron rings set into the crannog walls) also visible. Diver based survey was challenging but possible, with poor visibility slowing work and reducing the area that could be examined. A single piece of prehistoric pottery was found on the loch bed.

NB 21148 40955 Survey work at Loch Bhorgastail mapped the loch and surrounding landscape. Diver based survey was highly successful with good visibility. This allowed for the identification of numerous Neolithic pottery fragments in association with the artificial islet. No material culture from later periods was encountered, indicating a Neolithic date as being highly likely. Diagnostic sherds were recovered and are currently with Dr Mike Copper for analysis.

NB 21684 43805 Survey work at Loch Langabhat mapped the loch bed and surrounding landscape. A significant amount of Neolithic pottery was found underwater, in association with the artificial islet through diver survey. No later material culture was identified, strongly indicating a Neolithic date for construction.

Archive: Stornoway Museum (intended)

Funder: British Academy, Leverhulme Trust, and Honor Frost Foundation

Fraser Sturt and Duncan Garrow – University of Reading

(Source: DES, Volume 18)

NB 21684 43805 Following on from underwater diver and geophysical surveys carried out in 2016, a small-scale excavation and photogrammetric recording were carried out, 21–28 July 2017, on the small artificial islet or crannog at Loch Langabhat. The work aimed to establish a better understanding of the construction methods used in building the artificial islet, to establish the presence/absence of any buildings or other architectural features, to recover any archaeological material associated with the islet itself (in addition to the substantial quantities recovered previously from the loch bed around it), and to record the islet’s form both below and above water.

After initial vegetation clearance of the whole island, a single 2m wide trench was excavated across the centre of the islet. This trench was subsequently extended at its northern end to both the W and E in order to investigate features encountered. The stone architecture of the islet was revealed to have been constructed around a natural rocky crag that extended above the water level across much of the island’s extent. This natural feature had been augmented

through the construction of a large ring of stones, enclosing a slightly lower, relatively flat ‘base’. The main archaeological feature identified was a small, approximately oval (c3.0 x 1.5m), stone-walled structure situated just to the W of the island’s central point; this is probably best interpreted as a small shelter or hut. On its western edge, the structure’s wall appeared to run directly into the outer stone ring of the islet, suggesting that these two features were probably contemporary. The occupation deposits associated with the structure were dark and charcoal-rich. Pieces of worked quartz, a single flint scraper and sherds of Hebridean Neolithic pottery were recovered from these, confirming its original Early Neolithic date. Samples of young wood charcoal were obtained for radiocarbon dating (results pending).

In addition to the excavation, we also undertook under and above-water photogrammetric recording of the islet, enabling the construction an accurate 3D model of the site in its entirety. Palaeoenvironmental cores were also obtained from the loch bed to the E of the islet.

Archive: Museum nan Eilean, Stornoway (intended)

Funder: British Academy, Leverhulme Trust and Society of Antiquaries of London

Duncan Garrow – University of Reading

(Source: DES, Volume 18)