Uamh an Ard Achadh (High Pasture Cave) & Environs Project, Strath, Isle of Skye 2009 (NGR NG 5943 1971)
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Uamh an Ard Achadh (High Pasture Cave) & Environs Project, Strath, Isle of Skye 2009 (NGR NG 5943 1971) The Preliminary Assessment and Analysis of Late Prehistoric Cultural Deposits from a Limestone Cave and Associated Surface Features Data Structure Report - HPC006 West Coast Archaeological Services Archaeological & Ancient Landscape Survey Broadford Environmental Group West Coast Archaeological Services Archaeological and Ancient Landscape Survey Broadford Environmental Group July 2010 Grant aided by: Historic Scotland The Society of Antiquaries of Scotland Highland Council Highland 2007 Fund Western Isles, Skye & Lochalsh LEADER+ Uamh an Ard Achadh (High Pasture Cave) Strath, Isle of Skye 2009 (NGR NG 5943 1971) The Preliminary Assessment and Analysis of Late Prehistoric Cultural Deposits from a Limestone Cave and Associated Surface Features Data Structure Report - HPC006 Authors: Steven Birch Martin Wildgoose George Kozikowski Contributors: Fraser Hunter National Museums Scotland Dawn MacLaren National Museums Scotland Alan Saville National Museums Scotland Kirsty Bennell National Museums Scotland Marion O’Neill National Museums Scotland Ann MacSween Historic Scotland Carrie Drew University of Durham Emma Horton University of Durham Mike Church University of Durham Sheena Fraser University of Edinburgh Kath McSweeney University of Edinburgh Jo McKenzie University of Bradford Mike Cressey CFA Archaeology Ltd Antonia Craster AOC Archaeology Group Conservation Department West Coast Archaeological Services Sealladh Alainn 4 Upper Breakish Isle of Skye IV42 8PY Tel: 07867 651886 Email: [email protected] 2 Contents Page 3 List of Figures 6 List of Plates 6 List of Tables 7 1. Summary 8 2. Introduction 12 2.1 General 12 2.2 Background 12 2.3 Objectives 13 2.4 Layout of this Report 16 2.5 Discovery and Excavation in Scotland 16 2.6 Wider Publication 16 2.7 Archiving and Finds Disposal 17 2.8 Acknowledgements 17 3. Methods 18 3.1 General 18 3.2 Assessment of Desk-Based Sources 18 3.3 Field Survey 19 3.4 Excavation and Sample Processing 20 3.5 Archaeological Data Analysis 21 4. Fieldwork Results 21 4.1 Strath Suardal Landscape Survey 21 4.2 Landscape Survey and trial Excavation – 2010 22 4.3 Excavation Results 22 4.3.1 General 22 4.3.2 Trench 2 22 4.3.3 Trench 15 30 4.3.4 Trench 19 34 4.3.5 Trench 20 39 4.3.6 Test Pit Trench 4 40 4.3.7 Test Pit Trench 5, 6 and 7 40 4.3.8 Test Pit Trench 9 42 4.3.9 Test Pit Trench 8 42 4.3.10 Test Pit Trench 10 42 4.3.11 Uamh an T-Sill (Cave of the Seed): Trench 1 43 4.4 Discussion 44 3 5. Small Finds Assessment 46 5.1 General 46 5.2 High Pasture Cave: Assessment Report on Small Finds 46 5.3 Report on the Pottery 53 5.4 Fire-Cracked Stone and Preliminary Analysis of Stone Tools 53 5.5 Osteological Analysis of Bone and Antler Artefacts 54 6. Environmental Analysis 54 6.1 General 54 6.2 Analysis of Ecofacts 55 7. Palaeoenvironmental Assessment of the Ecofacts and Isotope Analysis 55 7.1 Analysis of the Animal Bone 55 7.2 Analysis of Charred Plant remains 56 7.3 Analysis of Burnt Bone 67 7.4 Analysis of Fish and Shellfish 75 7.5 Analysis of Charcoal 76 8. Radiocarbon Dating Programme and Preliminary Site Phasing 76 8.1 Radiocarbon Dating Programme and Results 76 8.2 Preliminary Site Phasing 83 9. Discussion 83 10. Recommendations for Further Work 89 10.1 Introduction 89 10.2 Cave Morphology Survey 90 10.3 Field Survey 90 10.4 Programme of Excavation 90 10.5 Programme of Post-Excavation Analysis 91 10.6 Publication and Dissemination of Information 92 11. References 95 4 Appendix 1: Context Lists by Trench 100 Appendix 2: List of Features by Trench 124 Appendix 3: Digital Images Register 141 Appendix 4: Field Drawing Register 155 Appendix 5: Finds Register by Trench 159 Appendix 6: Samples Register by Trench 170 Appendix 7: Burnt Plant Remains Spreadsheet Data 175 Appendix 8: Names and Addresses of Contributors 177 Plate 1 – Recording Trench 1 in Uamh an T-Sill 5 List of Figures 1 - Location maps for the High Pasture Cave site 14 2 - 2009 trench location plan 23 3 - Stairwell F2.23 plan, section and image 25 4 - Plan showing enclosure wall F15.14 and stairwell F2.23 32 5 - Plan of lower walkway F15.37 34 6 - Plan showing enclosure wall F15.14 and location of trenches 36 7 - Plan of ard marks and cut features in Trench 19 38 8 - Chart showing overall preservation of cereal grains from site 59 9 - Graph showing ratio of symmetrical to asymmetrical grains of barley 60 10 - Graph showing composition of cereal grain assemblage from site 60 11 - Burnt grain sample size by context 61 12 - Breakdown of weed seed assemblage from site 61 13 - Calculated grain concentrations by context at HPC 62 14 - Graph showing distribution of burning of bone over assemblage 71 15 - Radiocarbon dates falling within the range 800BC to 500BC 80 16 - Radiocarbon dates falling within the range 800BC to 500BC 81 17 - Radiocarbon dates falling within the range 400BC to 200BC 81 18 - Radiocarbon dates falling within the range 350BC to 150BC 82 19 - Radiocarbon dates falling within the range 200BC to AD150 82 20 - Plan of floor deposits in Bone passage relating to major phases of activity 84 21 - Distribution of querns/quern fragments on site (all phases) 88 22 - Distribution of finds relating to metalworking on site (all phases) 89 23 - SE facing section through Trenches 2 and 15 including stairwell F2.23 93 24 - NW facing section through Trenches 2 and 15 94 List of Plates 1 - Recording Trench 1 in Uamh an T-Sill 5 2 - Excavations in progress – May 2009 11 3 - Excavations taking lace in Trench 19 18 4 - Stairwell F2.23 before excavations in 2009 26 5 - Final phase of stairwell F2.23 and landing from the E 27 6 - Stairwell steps F2.24 leading to the head of the stairwell 27 7 - Stairwell F2.23 from the W 28 8 - Granite hearths F2.26 and F2.27, an back slab F2.28 28 9 - Stairwell F2.23 showing hearth back slab F2.28 29 10 - Stairwell F2.23 showing hearth back slab from the SE 29 11 - N elevation of enclosure wall F15.14 (F15.39) 31 12 - SW facing section through enclosure wall F15.14 in Trench 15 33 13 - Paving F15.42 subsiding into backfilled cave entrance, Trench 15 33 14 - Trench 19 looking E showing wall F19.12 and context C19.11 36 15 - Trench 19 looking NW showing wall footings (F19.12) 37 16 - Trench 19 showing features pre-dating formation of the burnt spreads 37 17 - NE facing section in Trench 20 showing compacted burnt spread deposits 40 18 - NE facing section through test trench TP6 41 19 - Slab-built hearth F1.01 in Trench 1, Uamh an T-Sill 44 20 - Coarse cobble tools from the 2009 excavations at HPC 49 21 - Quern rubber recovered from the lower walkway F15.37 51 22 - Pottery recovered during the 2009 excavations at HPC 54 23 - Backfill/closure deposits in lower walkway F15.37 87 6 List of Tables 1 - Summary of small finds assemblage 47 2 - Summary of coarse stone tool assemblage 48 3 - Preservation class of burnt plant remains 58 4 - Contexts examined for burnt bone 68 5 - Weight of burnt bone fragments 69 6 - Burnt bone fragments over 10g 69 7 - Complete bones from assemblage 69 8 - Percentage distribution of burning by weight/mesh size 70 9 - Percentage distribution of burning by weight/trench 71 10 - Species identified from contexts 72 11 - Bone fragments per anatomical area assigned to species 73 12 - Frequency of modifications noted 74 7 1. SUMMARY 1.1 Background 1.1.1 This report presents the results of field survey, excavation and preliminary analysis undertaken at Uamh an Ard Achadh (High Pasture Cave), in the Parish of Strath, Isle of Skye (NGR NG 5943 1971), carried out between April 2009 and May 2010 by West Coast Archaeological Services and Archaeological & Ancient Landscape Survey. 1.1.2 Fieldwork was undertaken as a result of preliminary rescue work and evaluation at the site between 2002 and 2004 (Birch et al, 2003; Birch et al, 2005), which included the removal of archaeological deposits from the cave that had been disturbed by speleologists visiting the site during 1997. 1.1.3 Preliminary analysis of the small finds recovered from the cave suggested activity at the site during the later prehistoric period, while radiocarbon assays indicate periodic, but continual use of the site between the 7th century BC and the 1st century AD. However, a group of small finds recovered from the cave and surface deposits and prehistoric ard marks, backed up by a radiocarbon dates obtained on wood charcoal, provide evidence of earlier activity at the site (see Section 8). 1.1.4 Additional fieldwork carried out at the site between 2005 and 2008 revealed a complex sequence of archaeological deposits containing large quantities of ecofactual material and a well-preserved faunal assemblage (Birch et al, 2008). A wide range of small finds was also recovered from the excavation including stone, iron and bone tools, ceramics and evidence of metal and antler working. Excavations at the surface, which focused on the investigation of a former blocked entrance to the cave, uncovered a deep sequence of archaeological deposits containing significant quantities of artefacts and ecofacts. 1.1.5 In Trenches 2 and 15 these well-stratified deposits exceed 3 metres in depth and were found to contain lenses of organic-rich sediments interspersed with peat and wood ash layers, associated with a succession of massive hearths.