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Cnoc Sligeach, Shell Midden 270 m south east of Airigh Na Creige

A Scheduled Monument in Kintyre and the Islands, Argyll and Bute

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Latitude: 56.0224 / 56°1'20"N

Longitude: -6.218 / 6°13'4"W

OS Eastings: 137266

OS Northings: 689084

OS Grid: NR372890

Mapcode National: GBR CD1S.SSR

Mapcode Global: WGYFP.GW9J

Entry Name: Cnoc Sligeach, Shell Midden 270 m SE of Airigh Na Creige

Scheduled Date: 10 October 2016

Source: Historic Environment Scotland

Source ID: SM13580

Schedule Class: Cultural

Category: Prehistoric domestic and defensive: shell midden

Location: Colonsay and Oronsay

County: Argyll and Bute

Electoral Ward: Kintyre and the Islands

Traditional County: Argyllshire


The monument is a partially excavated prehistoric shell midden probably dating to the late Mesolithic or early Neolithic around 4500-3400BC. The midden is visible as a large conical-shaped, grass-covered mound with a smaller midden mound located 5m to the southwest. The larger mound measures approximately 38m in diameter and stands around 3.2m above ground level at its highest point. The smaller mound measures approximately 15m in diameter and stands 0.5m above the ground. The midden is located at a height of around 10-15m above OD within an area of rocky outcrops and raised beach deposits approximately 200m inland from Port Dhun a' Gharaidh on the northeast coast of Oronsay.

The scheduled area is irregular on plan to include the remains described above and an area around them within which evidence relating to the monument's construction, use and abandonment is expected to survive, as shown in red on the accompanying map.

Source: Historic Environment Scotland

Statement of Scheduling

The cultural significance of the monument is expressed as follows:

Intrinsic Characteristics

Aerial photographs indicate that lazybed or rig and furrow farming was practiced around the midden and this may have involved the removal of midden material to improve soil quality. Excavations in the late 1800s, early 1900s, and during the 1970s indicate that the midden deposits extend at least 25m to the southeast from the top of the larger mound and to a depth of 1.7m. These excavations also identified structural remains including hearths, stone-filled post holes and other features, as well as lithic and organic artefacts including anvil stones and barbed bone implements. There is potential for survival of further midden remains in unexcavated parts of the monument which can enhance our knowledge of settlement in the Inner Hebrides during the late Mesolithic and early Neolithic periods.

The monument represents a focal point for coastal resource gathering probably during the late Mesolithic and early Neolithic periods. The pattern of midden deposits at Cnoc Sligeach suggests a complex sequence of occupation with the accumulation of midden material at two known locations. Carbon dating of organic objects suggests an early Neolithic date for the final phase of dumping of midden material between 5015± 210 BP and 6010 ± 450 BP. The age of the earlier levels of occupation at Cnoc Sligeach is less well understood but could be revealed by further investigations of the deeper midden deposits.

Contextual Characteristics

Today, Cnoc Sligeach is situated on an outcrop of rock around 200m from the sea. However, at the time of the site's occupation, relative sea levels were higher and the sea reached this point. This location would have offered the occupants of Cnoc Sligeach ease of access to a ready supply of shellfish and other marine resources.

Archaeologists consider Cnoc Sligeach the most extensive of a group of Mesolithic and Neolithic midden sites on Oronsay that evidence occupation by prehistoric hunter gatherers. In addition to Cnoc Sligeach, there are two middens known as Caisteal nan Gillean I & II (SM6288) located approximately 1.7km to the south west of Cnoc Sligeach and a third midden known as Cnoc Coig (SM13655) located 1.3 km to the west-southwest. As a group, these sites provide key evidence for mesolithic and early neolithic settlement of the islands of Western Scotland.

Although other Mesolithic sites are recorded on the nearby islands of Colonsay, Islay, Jura, Coll and Mull, the only known and comparable monument in form and in the extent of the recorded assemblage of artefacts outside of Oronsay is the shell midden on Risga (SM7829), Loch Sunart, approximately 40km to the north.

Associative Characteristics

There is a long history of investigation of Cnoc Sligeach – 'the shelly mound'. Artefacts arising from Galloway's investigations in 1884 are held by the National Museums of Scotland; the archive from Bishop and Buchanan's investigations 1911-13 is held by the Hunterian Museum, Glasgow. The excavations undertaken by Mellars in the 1970s are also well documented and, taken together with more recently published scientific analysis of the Oronsay middens, have significantly added to our understanding of Mesolithic hunter gatherers in Scotland.  


National Importance

The monument is of national importance because of its potential to make a significant addition to our understanding of occupation of the islands of western Scotland during the late Mesolithic and early Neolithic periods. Although there have been various phases of excavation on the site, substantial archaeological deposits are expected to survive that can provide important insights into the relatively understudied transition from the Mesolithic to the Neolithic. Cnoc Sligeach remains an impressive monument in the landscape and is the most extensive site of an important group of prehistoric middens on the island of Oronsay, one of the largest concentrations of such sites in the UK. Our understanding of the distribution and character of shell middens, and methods for gathering coastal and marine resources in prehistoric Scotland would be diminished if this monument were lost or damaged.

Source: Historic Environment Scotland



Historic Environment Scotland reference number Canmore ID 37801 (accessed 28/06/2016).

The site is recorded as Cnoc Sligeach (WoSAS 2400) on The Highland Council's Historic Environment Record.

Anderson, J., 1898, Notes on the contents of a small cave or rock shelter at Druimvargie, Oban; and of three shell mounds on Oronsay, Proceedings of the Society of Antiquaries of Scotland 32, 298-313, UK

Buchanan, M., 1911, Oronsay 1911, Unpublished document held by the Hunterian Museum, University of Glasgow (ref. P17-41 (Bu, UK

Fieller, Gliberton & Timmins, 1987, Sedimentary Analysis of the Shell Midden Sites, in Mellars, Excavations on Oronsay: prehistoric human ecology on a small island, Edinburgh

Grieve, S., 1885, The Great Auk or Garefowl (Alca impennis, Linn.): Its History, Archaeology and Remains, Jack, London

Jardine, W., 1978, Radiocarbon ages of raised-beach shells from Oronsay, Inner Hebrides, Scotland: a lesson in interpretation and deduction, Boreas, Vol. 7, pp.183-196, UK

Jardine, W., Jardine, D., 1984, Minor excavations and small finds at three Mesolithic sites, Isle of Oronsay, Argyll, PSAS, Vol 113, pp.22-34, UK

Mellars, P., 1987, Excavations on Oronsay: prehistoric human ecology on a small island, Edinburgh

Mercer, J., 1968, Stone tools from a washing-limit deposit of the highest post-glacial transgression, Lealt Bay, Isle of Jura'. Proc Soc Antiq Scot 100, 1–46, UK

Mercer, J., 1980, The Palaeolithic and Mesolithic occupation of the Isle of Jura, Argyll, Scotland, Almogaren 9-10, pp.347-67, UK

Pollard, T., Atkinson, D. & Banks, I., 1993, Risga (Ardnamurchan Parish), Mesolithic shell midden; prehistoric occupation site, Discovery and Excavation in Scotland, Council for Scottish Archaeology, UK

Wicks, K., Pirie, A. & Mithen, S., 2013, Settlement patterns in the late Mesolithic of Western Scotland: the implications of Bayesian analysis of radiocarbon dates and inter-site technological comparisons, Journal of Archaeological Science, pp.1-17, UK


HER/SMR Reference

Source: Historic Environment Scotland

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