Evidence of a new Iron Age occupation site is presented from a site located at the southern edge of a former tidal estuary in western Colonsay. A radiocarbon date of between the 1st–2nd centuries BC is significant in a regional context, being the first of this period from the island. Recovered burnt occupation debris includes cattle bone, marine (limpet and periwinkle) shell and ceramics along with a terrestrial snail shell and carbonised macroplant assemblage. The site was identified from geophysical survey (magnetometry and resistivity) focused at an earlier 5th–4th millennia BC shell midden. The discovery highlights the value of alternative field techniques and looking beyond fortified sites to find more elusive settlement evidence

Campbell, Ewan

Ceron-Carrasco, Ruby

Finlay, Nyree

Housley, Rupert

Huggett, Jeremy

Smith, Catherine

English

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Iron Age occupation evidence from Port Lobh, Colonsay (Scottish Inner Hebrides)

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      Finlay, N., Campbell, E., Ceron-Carrasco, R., Housley, R., Huggett, J. and Smith, C. (2019) Iron Age occupation evidence from Port Lobh, Colonsay (Scottish Inner Hebrides). Scottish Archaeological Journal, 41(1), pp. 119-123.     There may be differences between this version and the published version. You are advised to consult the publisher’s version if you wish to cite from it.    http://eprints.gla.ac.uk/174259/              Deposited on: 27 November 2018                       Enlighten – Research publications by members of the University of Glasgow http://eprints.gla.ac.uk   Author Original paper accepted for publication in Scottish Archaeological Journal Vol 41  Iron Age occupation evidence from Port Lobh, Colonsay (Scottish Inner Hebrides)  NYREE FINLAY*, EWAN CAMPBELL*, RUBY CERÓN-CARRASCO1, RUPERT HOUSLEY2, JEREMY HUGGETT* and CATHERINE SMITH3  Corresponding Author: Nyree Finlay Nyree.Finlay@glasgow.ac.uk * Archaeology, School of Humanities/Sgoil nan Daonnachdan, University of Glasgow, Glasgow G12 8QQ, Scotland.  1Conservation Directorate, Historic Environment Scotland | Àrainneachd Eachdraidheil AlbaLongmore House, Salisbury Place, Edinburgh, EH9 1SH  ruby.ceron-carrasco@hes.scot 2 Department of Geography, Queens Building, Royal Holloway University of London, Egham, Surrey TW20 0EX. Rupert.Housley@rhul.ac.uk 3 Alder Archaeology Ltd, 55 South Methven Street, Perth, PH1 5NX. csmith@alderarchaeology.co.uk  SUMMARY Evidence of a new Iron Age occupation site is presented from a site located at the southern edge of a former tidal estuary in western Colonsay. A radiocarbon date of between the 1st -2nd centuries BC is significant in a regional context, being the first of this period from the island. Recovered burnt occupation debris includes cattle bone, marine (limpet and periwinkle) shell and ceramics along with a terrestrial snail shell and carbonised macroplant assemblage.  The site was identified from geophysical survey (magnetometry and resistivity) focused at an earlier 5th- 4th millennia BC shell midden. The discovery highlights the value of alternative field techniques and looking beyond fortified sites to find more elusive settlement evidence.    KEYWORDS: terrestrial snail, shell midden, Dùn Gallain, geophysical survey     National and regional archaeological research frameworks have identified non-fortified Iron Age settlement sites as a key research priority (Hunter & Carruthers 2012, Regan 2017). In this note we draw attention to Iron Age occupation evidence discovered during fieldwork at the late 5th- early 4th millennia cal BC shell midden site at Port Lobh, Colonsay (Figure 1; Finlay and Jardine 2015, Finlay et al in prep.).  [insert Figure 1]   Geophysical survey (resistivity and magnetometry) was undertaken over a 80m by 40m area of rough pasture used as a golf course (for further data presentation see Finlay 2007). Magnetometry survey (using a Bartington Grad 601 single sensor by the same operator and a sensitivity of 1.0nT, n-s traverse) identified a diffuse area of individual dipolar responses and very subtle negative readings, in the south east of the survey area and 44m to the east of the main shell midden mound under investigation. No traces of associated substantial structural remains were identified in the resistivity survey.  A small test-pit (PL1A) was subsequently excavated (Figure 1, NGR135766 692720) to assess whether these geophysical anomalies were indeed indicative of further shell midden and to recover potential dating material. This revealed that underlying topsoil (001) was a sandy-silt (002) with occasional limpet and periwinkle shell fragments. Below this was compacted blackish-brown sandy silt (003) which contained occasional fragmentary limpet and terrestrial snail shells, a single burnt ceramic body sherd, numerous crumbs of burnt ceramic, an abraded cattle astragalus and further unidentifiable mammal bone fragments. Under (003) was a blackish sandy-silt layer (004) with frequent poorly preserved marine shells, terrestrial snail shells, burnt mammal bone fragments and further crumbs of burnt ceramic. It (004) overlay yellow sand (005) where excavation ceased.   Analysis of the marine and terrestrial shell was undertaken by Ruby Cerón-Carrasco (see Finlay et al in prep. for methodology and identification guides). The limpet and periwinkles shells are eroded and most of the limpet is highly fragmented (Table 1).   Of the six terrestrial snail species identified (Table 2), Vallonia excentrica (Sterki 1893) predominates and is found in dry calcareous places: sand dunes, short-tufted grass and screes.   [Insert Table 1: Marine shells present] [Insert Table 2: PL1A: terrestrial snails present]  An AMS date of 2445±35BP (SUERC-16342 ∂13C: 0.8‰) was obtained from a single limpet shell from context 4 (Table 3).  [Insert Table 3: Radiocarbon date]  Although heavily burnt, the hand made ceramic, mostly surviving as burnt crumbs, include a single body sherd (9mm thick) with quartz inclusions, which falls within the range of Hebridean Iron Age pottery fabrics (Campbell 2002). The observed stratigraphy and assemblage suggests deposits indicative of domestic occupation food debris – cattle and other bone fragments, marine shells and the carbonised macroplant assemblage with some potentially wider environmental context from the terrestrial snails.  The identification of previously unknown Iron Age occupation activity, dated to 291-22 cal BC, is an important regional addition but there is currently little to contextualise it. The promontory fort of Dùn Gallain, Port Lobh (RCAHMS 1984, 90; Piggott & Piggott 1948, 90) is the closest fortified site and lies within several hundred metres, but like others on the island is undated. Work at Bheinn Bheag, North Colonsay has begun to redress the paucity of other settlement evidence with an excavation focus on smaller stone structures (Regan 2012). At Port Lobh, the successful results from geophysical prospection offer new and alternative evidence to assist in the identification of occupation deposits that highlight the gains in looking beyond walls.  ACKNOWLEDGEMENTS   Fieldwork was funded by small grants to NF from the British Academy (SG40312) and the Society of Antiquaries of Scotland. Our gratitude to Alexander Howard, Lord Strathcona, Colonsay Estates; Seamus McNeill, and the Colonsay Golf Club for permission and information on the sites. Thanks to the survey and excavation team of Natalie Bergman, Andrea Jackson, John Malcolm and Dene Wright and to Tessa Poller for processing the geophysical survey data. The site archive is deposited with the National Record of The Historic Environment, Historic Environment Scotland. Edinburgh.   REFERENCES Bronk Ramsey, C. 2009 Bayesian analysis of radiocarbon dates, Radiocarbon 51.1, 337-360. Campbell, E. 2002 The Western isles pottery sequence, in Smith, B and Banks, I (eds), In the shadow of the brochs, 139-144, Stroud. Finlay, N. 2007 Port Lobh 1, Colonsay. Geophysical Survey and test excavation. University of Glasgow: Unpublished report.  Finlay, N. & Jardine, G. 2015. Lithic artefacts and the availability of pebble-flint on Colonsay, Scottish Inner Hebrides, in relation to coastal changes. Scottish Archaeological Journal 36, 37–50  Finlay, N., Ruby Cerón-Carrasco, R., Rupert Housley, R.  Huggett, J., Jardine, W.J., Ramsay,S. Smith, C., Wright, D., Augley, J., and P.J. Wright nd. Calling Time on Oronsay: revising settlement models at the Mesolithic-Neolithic transition in western Scotland, new evidence from Port Lobh, Colonsay. Unpublished manuscript.  Hunter, F. and Carruthers, M. (eds) 2012. Scottish Archaeological Research Framework. Iron Age Panel Report. http://www.scottishheritagehub.com/content/iron-age-panel-report. Piggott. S. and Piggott, C M. 1948 Field work on Colonsay and Islay, 1944-45,  Proc Soc Antiq Scot 80 (1945-6), 83-103. RCAHMS 1984 Argyll. Volume 5. Islay, Jura, Colonsay and Oronsay. Edinburgh. Regan, R. 2012 Bhienn Bheag, Colonsay, Archaeological Test Pit Excavations, Data Structure Report. Kilmartin Museum.    Regan, R (ed) 2017 RARFA: The Iron Age: 700 BC - AD 500, Scottish Archaeological Research Framework: Society of Antiquaries of Scotland. http://www.scottishheritagehub.com/rarfa/ironage Reimer, P. J., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Bronk Ramsey, C., Grootes, P. M., Guilderson, T. P., Haflidason, H., Hajdas, I., Hatt, C., Heaton, T. J., Hoffmann, D. L., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., Manning, S. W., Niu, M., Reimer, R. W., Richards, D. A., Scott, E. M., Southon, J. R., Staff, R. A., Turney, C. S. M., & van der Plicht, J. 2013 IntCal13 and Marine13 Radiocarbon Age Calibration Curves 0-50,000 Years cal BP, Radiocarbon, 55.4.  FIGURE LIST AND CAPTION 1 Site Location Map, test-pit section and radiocarbon curve. © Crown copyright and database right 2018 Ordnance Survey (100025252).             TABLES Context Sample Species Adult Juvenile Broken shell Broken burnt shell 3  6A Limpet 2  ***  Periwinkle 8 5 ***  4 2A Periwinkle 21 17 ****   4A Limpet 3  **** ** Periwinkle 2 4 ****  Table 1 Marine shells present (Key for crushed shell for individual species: ** present, minimal amount, ***moderate amounts present, **** common, relatively large amounts).  Species/Context (sample) 3 (6A) 4 (4A) Vertigo pygmaea (Draparnaud, 1801) f  Helicella Itala (Linnaeus, 1758) vf  Cochlicella acuta (Müller, 1774) f  Cochlicopa lubrica (Müller, 1774) f vf Trochulus Hispidus (Linnaeus, 1758) f vf Vallonia excentrica (Sterki, 1893) sig sig Table 2 Terrestrial snails species present (vf= very few; f= few; sig= significant (i.e. dominant species). Test-pit/ Context/ Sample Material Age uncal BP ∂13C (‰) Lab Code 1 sigma (cal BC)  2 sigma (cal BC)  1A/004/ S4A Limpet shell Patella vulgata 2445±35 0.8 SUERC-16342 191-80 291-22 Table 3 Radiocarbon date. Calibration using Marine13 (modelled ocean average marine calibration curve of Reimer et al 2013) and the Oxcal v4.3.2 program of Bronk Ramsey 2009)  

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Iron Age occupation evidence from Port Lobh, Colonsay (Scottish Inner Hebrides)

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