Rubh’ an Dunain, Skye: 8000 Years of History

by Martin Wildgoose

Aerial view of the Rubh’ an Dunain peninsula

Members of NOSAS walking towards the tackman’s house on Rubh’ an Dunain. Canna is on the skyline.

A warm sunny Sunday in early June saw NOSAS members gathering in the Glenbrittle campsite, at the foot of the Cuillin Mountains. The view south was spectacular, Canna seemed unusually close and South Uist and Barra lay in the haze on the horizon. Close at hand the Rubha an Dunain peninsular stretched out to the left of the bay with a ribbon of made-up path promising an easy walk to the point where 8000 years of Skye’s history lies exposed to view. Just an hour and a half later the group paused to enjoying a mid-morning coffee prior to crossing the Slochd Dubh (Black Hollow) where a late 18^th century wall marks the boundary between Clan MacAskill and Clan MacLeod – but more of that later.

The first people to leave tangible evidence of their stay on the peninsula were Mesolithic hunter-gatherers who travelled throughout the islands off the west coast of Scotland on a seasonal round, in pursuit of food and tool resources. A site excavated at Kinloch on Rum (HER MHG 3987) between 1984 and 1986*, only a day’s boat journey away to the south west, may be the winter base for these pioneers. A small rock shelter (HER MHG4898) at Rubh an Dunain, partially excavated in 1932 by W Lindsay Scott**, contained many worked stone tools and the debris from their manufacture – evidence of repeated visits to the site during this period. Additionally a recently recorded lithic scatter on a terrace close to Loch na h-Airde shows that more sites of this period await discovery (the day in fact finished with NOSAS members happily picking fragments of worked bloodstone and mudstone out of a nearby burn).

Martin points towards Loch na h-Airde from just outside the rock shelter.

Experiments using a Quadcopter for Archaeological Aerial Photography

by Alan Thompson (NOSAS)

Introduction

I’ve had my Quadcopter for over a year now, had great fun flying it, and have produced many interesting images.  I recently showed a selection of images at a NOSAS evening, and was asked if I would write this blog and share some of the things I’ve learned along the way.

Of course the pictures are what it’s all about and even if you’re not interested in my comments, I hope you enjoy looking at them.

Background

Inspired by some of the wonderful aerial photos (APs) I’ve seen (for example on Canmore) I have long thought how good it would be to be able to take such pictures of our own archaeological sites.

For several years I have been interested in photogrammetry and experimented with that, especially of rock art where the production of a 3D surface and use of computer generated lighting and shadows can give some great effects.

In 2013 I began to investigate kite aerial photography (KAP) but the possibility of using a Quadcopter also emerged and I realised that technology and prices were moving so quickly that it might be a better option.  In early 2014 I decided that the only way to learn was to buy one.

The Quadcopter – getting ready to fly

Most amateur Quadcopters are sold with very wide angle cameras, with the intention of video recording, and also providing a pilot’s view (called first person view or FPV).  This is less than satisfactory for archaeological aerial photography, and so I bought a Quadcopter without a camera, with a view to fitting my own.

The camera is obviously critical, and it needed to be light (ideally <300g including battery), robust, of good enough quality, and with an interval timer.  Unfortunately I could find no such camera.  All those with interval timers are heavier, for example those used for kite aerial photography.  A solution can however be found in that a group of people spend their time hacking the software of Canon cameras (google CHDK) and provide a hacked version for some models which enables an interval timer to be run.

Having bought and hacked my camera and got the interval timer working I had to fit it to the Quadcopter.  The main problem is the high frequency vibration from the rotors which renders the pictures useless.  A suitable anti-vibration mounting was needed, all within the weight limit.

Next, to prepare for the first test flight.  The web (YouTube) is full of videos of alarming crashes and fly-aways.  The Quadcopter instructions are daunting saying that a first flight should be from the middle of a large field, with no wind and no people about.  There is also the matter of insurance (it could certainly hurt someone badly), and the possible need for a CAA licence.  The regulations here are changing quickly but at present as a hobby flier I can insure through the British Model Flying Association (BMFA), and (unlike a professional archaeologist) have no need of a CAA licence provided I fly within line of sight, avoid certain areas (eg near airports) and limit the height.  I would again emphasise that this is all very much in the news and changing and my observations here will quickly be out of date.

The first flight is bit nerve-racking, but set to auto mode the Quadcopter uses its own GPS and compass and is set so that (more or less) if you let go of the controls it just hovers where it is.  Flying in this mode is reasonably straightforward.  I have not dared try any of the advanced modes as yet.

Highland Hillforts

by Meryl Marshall (NOSAS)

The Atlas of Hillforts in Britain and Ireland project

Hillforts are one of the most prominent types of prehistoric monument seen across many parts of Britain and Ireland, and this hillfort project has recently been set up with the aim of producing a paper atlas and an online searchable atlas linked to Google Earth. It is a collaborative four year project between the Universities of Oxford and Edinburgh, and contributions from members of the public, either as individuals or as part of local field groups, are welcome.

Several members of NOSAS were interested in this project and a field day took place in May which nine attended. We visited three forts in the Drumnadrochit area which James McComas had suggested. The day was a great success even though the weather didn’t exactly co-operate and the overall impression was “damp” to say the least! The three forts of Dun Scriben, Craig Mony (Craigmonie) and An Torr were very different from each other – we took photos, made rough sketches and filled in the (reputedly) tortuous form provided on the website. The form proved to be not as formidable as we had anticipated and has been submitted to Strat Halliday who is the Scottish and Irish end of the project. If any members are interested in participating in the project or in joining the next NOSAS field day please contact Meryl Marshall.

More information about the project is available on the website

http://www.arch.ox.ac.uk/hillforts-atlas.html

The form to fill in is available at

http://www.arch.ox.ac.uk/files/hillforts/survey%20pro-forma%20web%20final%20v2.pdf

and notes and guidelines are at

http://www.arch.ox.ac.uk/files/hillforts/survey%20notes%20for%20guidance%20web%20final%20v2.pdf

Producing drawings of hillforts

A drawing or sketch of a site, even if it is not precisely to scale, gives so much more information than a written description. Ideally it would be good to produce a plane-table drawing but this is not always a convenient method as it is time consuming and involves carrying heavy equipment to remote and inaccessible places. So when doing the recent surveys at Drumnadrochit we experimented with several methods of survey: using tape and offset, pacing and GPS waymarks. A draft sketch on permatrace was produced but, as usual, it was a bit messy – the words “dog’s breakfast” came to mind! A tidy final drawing was needed, so using a further piece of permatrace and a 4H pencil, I traced the site using hachuring as per RCAHMS guidelines, with annotations to clarify some of the features; I then scanned the result, see sketch of Craig Mony Fort. For me this method of drawing up is new and I have not perfected the technique yet, but Ian Parker of RCAHMS was helpful in giving advice and suggestions, and also his own drawing below.

Craig Mony, Drumnadrochit, by Meryl Marshall

Craig Mony, Drumnadrochit, by Ian Parker

Cnoc Tigh and Tarlogie Dun Excavations (Iron Age Round Houses)

by David Findlay (NOSAS)

These excavations, in April and July 2014, were led by Candy Hatherley and form part of the University of Aberdeen Northern Picts Project. Cnoc Tigh (see also our earlier blog entry) and Tarlogie Dun are Iron Age round houses situated on the north coast of the Tarbat Peninsula in Easter Ross. They are both on the high ground about 200m back from the coast giving them spectacular views across the Dornoch Firth to Sutherland and up the Sutherland coast. Neither site is naturally defensive and, though both have watercourses to one side creating a gorge and a steep bank to the sea on another side, that still leaves two sides open to the surrounding countryside.

The NOSAS team at Tarlogie, looking N (David Findlay)

They differ from the three duns excavated by the Aberdeen University Team in 2013 in that these were all on the south side of the Tarbat Peninsular and were relatively defensible due to the natural features, although Tarrel is overlooked by the cliff on the landward side.

Both Cnoc Tigh and Tarlogie appear to date from about 400 BC with occupation at Tarlogie lasting for 800 years to about 400AD. I do not know of any dates yet for the latest occupancy at Cnoc Tigh although I understand that suitable charcoal samples have been taken for dating.

The 2014 excavations at both sites reveal severely robbed and damaged stone walls; there are discernible facing walls in a few locations but largely only the fill remains. Both sites show a lot of evidence of the structures changing with time.

Excavations on the Tarbat Peninsula: Scotsburn (Iron Age Broch or Dun) Part 2

By Vaidutis Žutautas (University of Aberdeen)

Just above the left bank of steep wooded ravine of the Balnagown river, remnants of a prehistoric dun (NH77NW 6, NH 7148 7616) sit on the sloped eminence surrounded by a complex of structural features, arguably belonging to it. The site has been known for a long time, as it still stands prominently and it is likely that it has not been disturbed by agricultural activities throughout centuries, although some possible robber trenches can be seen on the E side of the dun wall. Prevailing arguments suggesting that the roundhouse could carry the title of ‘a broch’ were usually subjected to narrow over-surface interpretations by only taking into consideration structural features such as the diameter of the house (13m), wall thickness (~6m on the surface) and its elaborate compounds that skirt the dun. However no comprehensive evaluation has been done since 1968 when OS did a basic descriptive survey and designated the structure as a dun.

In order to expand the distributional scope of the late prehistoric structures in Tarbat peninsula and its environs, the team of archaeologists from the Aberdeen of University has targeted Scotsburn Dun in seeking to evaluate the underlying archaeology. A permission to locate 3m x 20m trench and extract effective dating material that would provide a chronological framework for the site was given by Historic Scotland Scheduled Monument Consent. Additionally, to answer perhaps the most intriguing question­- whether the structure is a broch or a complex dun – authorisation was given to uncover the roundhouse wall and identify its external morphology that would allow drawing assumptions regarding its structural classification.

Since this excavation was ongoing along other two digs in the area (Cnoc Tigh and Tarlogie Dun), the logistics were relatively subordinate especially in terms of people on the site. At least two archaeologists were working at Scotsburn with a kind help from volunteers living in the region. Yet even said that, the dig has not been crowded and therefore dealing with exceptionally complex archaeology and nearly 40m³ of deposited rubble extended original ten day dig to a four and a half week mattocking paradise.

Realising the complexity of the site on the first day, it was decided to open 2m x 20m trench stretching NW-SE encompassing area between the roundhouse and the enclosure wall and another two earthworks giving another 6,8m extension for vegetation, top soil and limited latest collapse deposit clearance from the dun wall. Unsurprisingly, it has been a highly demanding task to define structural features and reach occupation horizons by removing tons of collapsed stones; this process took nearly two weeks mainly allocating labour in two areas: a) between the roundhouse wall and the enclosure wall, and b) between the enclosure wall and the first earth bank.

Aerial picture of the entire trench showing mid-excavation.

Excavations on the Tarbat Peninsula: Scotsburn (Iron Age Broch or Dun) Part 1

Mid Excavation Report by Oskar Sveinbjarnason (University of Aberdeen)

The excavation at Scotsburn House aims at dating the occupation as well as trying to discern if the site is a broch or a dun.

Outer wall face of Scotsburn “house” with Roland.

A single trench 20m long and 2m wide was placed over the building wall and extends northwards over four rampart banks. The round house wall has been revealed but it has not shown yet if it is a broch or a dun. The ramparts have so far shown a nice stone facing. The site is getting more complex as “new“ walls have been uncovered in the trench. The relationship between these walls and the ramparts and ditches is being investigated.

Photo from the trench with Leaf and James.

The lower left corner of the picture shows one of the banks. Behind Leaf and James is another bank and towards upper right corner is the Scotsburn house wall.

Following Oscar’s report an iron age road surface was uncovered in this ditch.

Excavations on the Tarbat Peninsula: Cnoc Tigh (Iron Age Round House)

by Oskar Sveinbjarnason (University of Aberdeen)

The excavation started as planned on the 22nd June. A 15m long trench and 10m wide was opened over the northern part of the dun. It took 2 days to open up the area (gorse removal and grass) and as the surrounding field was under crop, a JCB was not able to access the site and speed up the opening. It soon became apparent that the site has been largely robbed of stones, likely during the 19th – 20th Century, possibly to make the enclosure which sits on top of the dun. The quarry holes can still be seen. It was a hard task to plan and remove this later enclosure, mainly due to the amount of rubble and the fact that the enclosure was little more than tossed up earth and stone bank (we can firmly assume that this is not the Castle Corbet) and blended in with the dun itself.

Picture showing the surviving outer dun wall. The rubble to the left is a collapse which hid this outer wall face.

In the trench the outer dun wall face was harder to find than we expected and is it due to the large amount of collapse from the dun wall core outwards and collapse from the enclosure on top of it as well. It was towards the end of week 2 when we finally figured out where the outer dun wall was located and which made the site nicer and easier to understand.

The dun wall turned out to be a complex construction with multiple stages of construction now visible. Initially it seems to have started out as a round house with about 1.5m thick wall. Up against this wall, additional 2.5m of extra wall was added, making the wall about 4m thick.