First Scientific Dates Tell Story Of Skomer’s Prehistoric Island Landscape

Archaeologists have obtained the first accurate dates for prehistoric settlement on Skomer Island, Pembrokeshire, a landscape famed for its wildlife and for the survival of its ancient field systems, which are among the best preserved anywhere in Britain.
 
Excavations in 2014 at a prehistoric mound of burnt and fire-cracked stones on north Skomer, once used to boil water for cooking, have produced the first calibrated radiocarbon dates for farming settlement on this renowned island. The mound sealed a land surface dated by charcoal to between 520-458 cal BC, the early Iron Age. A cattle tooth deposited in the cooking mound while it was still in use was dated to between 116-54 cal BC, centred on 85 cal BC, the late Iron Age.

In April 2014 a small team of archaeologists was permitted to open the very first modern excavation trench in the island’s history, to retrieve dating and environmental samples to better understand the long and complex history of prehistoric settlement and farming on Skomer. This followed three years of collaborative, non-invasive research between staff of the Royal Commission, The University of Sheffield and Cardiff University, working closely with the Wildlife Trust of South and West Wales and Cadw.

Burnt mounds accumulated from a particular prehistoric cooking practice, which involved heating stones in a fire and then placing them into a water-filled wooden trough to boil the water. Once the water was boiling it could take around 3 hours to cook a joint of meat, with each successive cooking episode adding more waste burnt stones to the mound. The burnt mounds outside some of the roundhouse groups on Skomer Island are huge, and must have dominated the Iron Age landscape, alongside the conical thatched roofs of the houses.

Dr Toby Driver of the Royal Commission, Aberystwyth, explained:
‘Skomer is a fragile protected landscape, and our archaeological research to date has focussed on non-invasive investigation of the prehistoric fields and settlements. This has included new aerial photography, airborne laser scanning, ground geophysics and walkover surveys. Already we have discovered previously unknown Neolithic and Bronze Age ritual stone settings, and demonstrated that the field systems may date back to at least the later Bronze Age.’

 ‘But despite half a century of modern archaeological interest, we still had no scientific dates for the roundhouses and fields on Skomer. It was decided to target a prehistoric burnt mound or cooking mound of fire-cracked stones, which stands immediately outside one of the paired roundhouses. This mound built up from numerous cooking episodes in the adjacent house. Our excavation discovered a cattle tooth from within the mound of stones, which has now been radiocarbon dated to the late Iron Age. Beneath the mound we found a sealed land surface containing Neolithic or Bronze Age worked flint tools. A second radiocarbon date from blackthorn charcoal in the upper soil layers gave a an early Iron Age date, possibly from burning and clearance on the land, which showed our burnt mound and the houses it belongs to arrived after the early Iron Age. Both dates are accurate to within 62 years.’

‘These new dates confirm pre-Roman settlement on Skomer. Even so, the burnt mound covers a substantial earlier field wall showing that the island was already well settled and farmed in previous centuries.’

Find out more online

Photographs, maps and plans can be seen online at the Royal Commission’s online database www.coflein.gov.uk . Search for ‘Skomer’ to see all records, or ‘Skomer hut group 8’ to see a selection of the 2014 excavation photographs.

Direct link: http://www.coflein.gov.uk/en/site/420196/details/SKOMER+ISLAND+HUT+GROUP+8/

Links to related BBC news stories: http://www.bbc.co.uk/news/uk-wales-south-west-wales-17644413

More about the Skomer Island archaeological project

Skomer is a highly protected landscape famous for its puffins and other breeding seabirds, but it is also home to some of the best preserved prehistoric field systems and hut settlements anywhere in Britain. In 2011 the Royal Commission used airborne laser scanning (LiDAR) to comprehensively map the island’s field systems. This work discovered evidence for a longer chronology to the fields than had previously been thought. The Skomer Island Project built on this work in 2012 with the first use of geophysics on the island, which showed that unrecorded prehistoric fields and settlements survive beneath the modern fields in the centre of the island.

The Skomer Island Project team, Louise Barker and Dr Toby Driver (Royal Commission), Dr Bob Johnston (University of Sheffield) and Dr Oliver Davis (Cardiff University) would like to thank the Skomer Island Wardens, the Wildlife Trust of South and West Wales and Natural Resources Wales for accommodating the archaeological work and granting permission to work in a Site of Special Scientific Interest. They are also grateful to Cadw for Scheduled Monument Consent which allowed the work to proceed.

Appendix: the radiocarbon dates

SKOMER ISLAND
SUERC-54181 (GU34955)
Context: 107, charcoal derived from buried soil layer beneath burnt mound
Material: Prunus cf. Spinosa (probable blackthorn)
Radiocarbon age: 2439 ± 30 BP (before 1950 AD)
Calibrated date (95.4& probability): 519-459 cal. BC
SUERC-55129 (GU34956)
Context: 108, Find 24. Cattle tooth deposited in upper layers of burnt mound
Material: Cattle tooth: Cattle
Radiocarbon age: 2035 ± 31 BP (before 1950 AD)
Calibrated date (95.4& probability): 116-54 cal. BC

Recording the excavation trench through a cooking mound of burnt stones on Skomer Island. The exposed stone wall of the Iron Age roundhouse can be seen at the end of the trench.
Crown Copyright RCAHMW, DS2014_354_018

The Skomer Island Project team (L-R), Dr Oliver Davis (Cardiff University), Louise Barker (RCAHMW), Dr Bob Johnston (University of Sheffield), Dr Toby Driver (RCAHMW).
Crown Copyright RCAHMW, DS2014_354_006

Skomer Island. A 3D view of the prehistoric field systems (in red) overlying a terrain model generated from airborne laser scanning or LiDAR.
Crown Copyright. Environment Agency. All Rights Reserved. View generated by RCAHMW, Crown Copyright RCAHMW. LD2012_02_01

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A snapshot of Uplands Initiative work at Manod Bach, Gwynedd

Royal Commission staff members, Jon Dollery and Nikki Vousden, recently joined the Commission’s Uplands project co-ordinator, David Leighton, on a visit to Manod Bach, near Blaenau Ffestiniog. We shadowed archaeologists, Richard Hayman and Wendy Horton, who were undertaking a survey of the area as part of the Royal Commission led Uplands Initiative. The long-running project aims to survey and record archaeology on all moorland over 244m above sea level. Some 2380 square km has been surveyed to date. Each year the Royal Commission awards grants to enable teams of archaeologists to record monuments and features in some 150 square km of landscape. Before work on the ground proceeds an archaeologist within the Royal Commission examines all vertical aerial photographs held at the Commission and uses GIS software to produce maps of all archaeological features. This work is currently undertaken by Mapping Officer, Jon Dollery. The mapping guides archaeologists in the identification of features as they walk in parallel 30-50m transects across the landscape. It also helps them understand long linear features such as trackways, artificial watercourses or former field boundaries.

Manod Bach, mapped using 1940s RAF vertical aerial photographs. The red line depicts the boundary of the area under survey. Possible features are highlighted in order to guide archaeologists in the identification of features on the ground.

Conversely, archaeologists on the ground can identify small features such as stone-built cairns or prehistoric standing stones that may be too small for identification from the air.

Our field-walking resulted in the verification of numerous mapped features, including a sheep fold and an intricately built sheep wash utilising natural landscape features. It also resulted in the identification of features not visible on aerial photographs, including two mine shafts, one of which was previously unrecorded.

Archaeologists noting the detail of a sheep wash. Sheep would be held in a series of walled-in pens on the natural platform adjacent to the rock outcrop, before being released through the stream.

Water-filled mine shaft.

The fieldwork was a valuable opportunity to see how our desk-based work on air photograph interpretation aids the identification of features on the ground.

By Nikki Vousden.


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My First Week As Mapping Officer For The Royal Commission

My name is Jon Dollery and I’m the new Mapping Officer at the Royal Commission. Being a new member of the team and new to the Commission, I thought it would be a good idea to post a blog about my first week and to share with you my experiences and the type of work that I have been doing.

As many of you will know, the first day starting anywhere can be quite daunting, no more so than for myself starting at the Royal Commission! In the past, I have been involved with archaeological excavations in and around Wales. My most recent experience involved running the archaeological excavations at the National Botanic Garden of Wales, I have also had the opportunity to work alongside some of the Commission’s staff as well as hearing about some of the Commission's amazing partner projects.

At 9:30, Monday 17 June, staring up at the Commission’s offices in Aberystwyth, I felt extremely nervous to say the least. Luckily everyone within the office was really supportive and my first day flew by. In the morning I started my induction to learn about the Do’s and Don’ts of working within the office. In the afternoon I was introduced to the team I will be working with - the Data and Technology Team - and everyone was very friendly.

On Tuesday I started work on a project, involving aerial photographic mapping in conjunction with the Uplands Archaeology Initiative. My role in this project will be to use the aerial photographic collections within the Commission and GIS software to identify potential archaeological features that have so far not been discovered, which I can honestly say is one of the best jobs in the world! The area I have been looking at is residual moorland within north Monmouthshire which has some interesting archaeology. So far, I have found a few circular enclosures, lots of peat cutting trenches, a few potential sites for buildings as well as lots and lots of pillow mounds (rabbit warrens).

Also during the week, I completed the induction programme which has been very useful. I have met lots of new faces and have had a tantalising glimpse of future projects that I’ll hopefully be involved with... I can’t say much more really... apart from watch this space; July and August are going to be brilliant!

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