Spot that boundary…

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Spot the boundary. It’s very slight, but it is just about visible on the ground. Scroll down for the answer…

Having put my various datasets into the GIS environment (see previous posts), the time has come to put them to work. First up – and most time consumingly – to map the known coaxial boundaries within the national park. This might sound like an obvious thing to do, but many of them have not been accurately recorded before. Some of the large systems of Swaledale have been systematically surveyed as part of the Swaledale Ancient Land Boundaries Project (their website/reports are here) and several systems in Wharfedale (between Grassington and Kettlewell) have had attention paid to them by antiquarians and more recently (see Raistrick 1937, Horne & MacLeod 1995), but many are recorded in the HER only as a ‘coaxial field system’ without details pertaining to individual boundaries.

By using a combination of digitized sources, I have been able to map the remains of the boundaries in 24 known coaxial systems. Perhaps the most useful of these sources (beyond the HER, which gave me an idea where to look) was the aerial photographic imagery available through the ESRI ArcMap setup. Other sources of aerial photography are available, but mine was provided by Bing!, which worked out well as data provided by some of the others are not so clear for this part of the world. Where available, the lidar data complemented this photography nicely, illuminating lumps and bumps that were not otherwise visible due to the lighting or vegetation. It’s amazing, though not surprising, how much easier it is to get your head around a system when it’s seen from the air – and slightly ironic, considering the people who built it didn’t get to see it that way. Of course, the detail is always on the ground, but this approach gives a useful broadbrush overview – a starting point for further investigation.

The maps below show the coaxial system near Horton in Ribblesdale – like several of the other systems, you can walk though it (there is a Natural England self-guided walk through the nature reserve in which it is located here).

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Coaxial field boundaries at Horton in their topographical context. (Contour data provided by OS Terrain 5 data service via Digimap.)

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Coaxial field boundaries (in white) at Horton in their geographical context.

 

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…the boundary runs straight towards the camera, between the two red arrows. Much easier to see from the air (although, admittedly, this is a particularly-difficult-to-see example!).

Data and Deliberations: Part 2 Lidar

As you probably know, the availability of lidar data (lidar stands for Light Detection and Ranging) has taken the archaeology world by storm over the last decade or so. The collection of airborne lidar data involves sending out laser pulses from a plane, which are reflected back from the point at which they hit the ground (or any intervening objects). Given that the speed of the light is known, the distance each pulse has travelled can be calculated from the time it takes to return; in conjunction with very precise GPS positional data for the plane, the result is an accurate 3D location of each point in space, and therefore an accurate model of the land surface. This can then be viewed in a GIS, where it makes a superb tool for detecting subtle earthworks, such as coaxial boundaries, against background clutter.

Unfortunately, there is not 100% lidar coverage of the Dales yet. The lidar I am using has come from the  UK Environment Agency, who collect data as part of flood monitoring and environmental asset planning programmes and therefore target specific, required areas. The image below shows the 1m resolution (there is a point value for every square metre) lidar data available for the Yorkshire Dales National Park. It is very clear from this map that most of the data collection has focussed on the river valleys, with coverage often not (or only just) reaching the top of the valley sides. Which makes it difficult to rely on when prospecting for coaxials, which often, frustratingly, survive just above this level!

Figure 1: 1 x 1m lidar data for the Yorkshire Dales National Park (Data copyright Environment Agency 2015).

Figure 1: 1 x 1m lidar data for the Yorkshire Dales National Park (Data copyright Environment Agency 2015).

In places, however, coaxial field boundaries do show up clearly in the lidar data, running across the contour as in figure 2, and I have been mapping them from the lidar in conjunction with aerial photographs and maps, in order to characterise the individual systems. Lidar data can be viewed in various ways: figure 2 contains a simple 2D hillshade plot that ‘makes sense’ to the human eye, but various parameters can be exaggerated, or the point values used to analyse assorted elements of the terrain. The data can also be viewed in ‘3D’ (as in figure 3), which helps to visualise and understand relationships between the archaeology and the landscape. Usefully, it is also possible to drape other data sets over this digital elevation model – such as the aerial photography in figure 4.

Figure 2: Coaxial field system boundaries visible  north of Grassington in 1m resolution lidar.

Figure 2: Coaxial field system boundaries visible north of Grassington in 1m resolution lidar (Data copyright Environment Agency).

Figure 3: Hillshade plot  showing part of Upper Garsdale, viewed as a 3D surface model. It is possible to rotate and 'fly through' the model landscape. (Data copyright Environment Agency 2015.)

Figure 3: Hillshade plot showing part of Upper Garsdale, viewed as a 3D surface model. It is possible to rotate and ‘fly through’ the model landscape. (Data copyright Environment Agency 2015.)

Figure 4: The height data from the lidar has been used as a surface over which to drape this aerial photograph of Halton Gill, Littondale. (Data copyright Bing Maps/Microsoft/Environment Agency 2015.)

Figure 4: The height data from the lidar has been used as a surface over which to drape this aerial photograph of the valley side at Halton Gill, Littondale. (Data copyright Bing Maps/Microsoft/Environment Agency 2015.)

One of the bonuses of lidar data is the facility to alter the direction from which the (artificial) light source is shining on the landscape – depending on the orientation of individual features or their position in the topography, they may not be easily visible when illuminated from any given direction (as is the case in an aerial photograph, for example). Figure 5 shows the same medieval lynchets in Wharfedale illuminated from 3 different directions, and the difference this has on the visibility of the archaeology is very clear. The same goes for the height of the light source above the ground (think of the difference between viewing earthworks at midday and in late afternoon!). Obviously, while particular light directions and heights reveal more detail in landscapes, the flip side of this is that others cause detail to be obscured and it requires a little trial and error to work out which are the most advantageous light source positions.lynchets0lynchets45

Figure 5: Medieval lynchets near Grassington, Wharfedale, illuminated from 0º (top), 45º (middle) and 315ª (bottom) azimuth. Note how the visibility and prominence of features on different alignments varies under different lighting conditions. (Data copyright Environment Agency.)

Figure 5: Medieval lynchets near Grassington, Wharfedale, illuminated from 0º (top), 45º (middle) and 315ª (bottom) azimuth. Note how the visibility and prominence of features on different alignments varies under different lighting conditions. (Data copyright Environment Agency 2015.)

One way to get around going through 8 or 16 different images by hand for each area, is to use a combination of the images, which essentially includes the ‘best bits’ of each one. For my first foray into the world of computer coding – aided and abetted by my infinitely more code-minded colleagues – I am in the process of writing a piece of code that does this, by applying principal component analysis. You can see the difference between the images below…it’s often only subtle, but in places it may make interpretation just that bit more accurate.wharfe135a_06_07 copy wharfe090a_06_07 copy

Figure 5: The first two images show hillshade plots of Knipe Hill, Kettlewell, lit from 135ª and 90ª respectively; the third image shows the results of the application of principle component analysis, in which elements of these plots were combined with 6 others lit from various directions. Note how each emphasise different features. Click  to enlarge. (Data copyright Environment Agency 2015.)

Figure 5: The first two images show hillshade plots of Knipe Hill, Kettlewell, lit from 135ª and 90ª respectively; the third image shows the results of the application of principle component analysis, in which elements of these plots were combined with 6 others lit from various directions. Note how each emphasise different features. Click to enlarge. (Data copyright Environment Agency 2015.)

You can find out more about lidar here: http://content.historicengland.org.uk/images-books/publications/light-fantastic/light-fantastic.pdf/

This is hardly a scientific test, but…

…the following ‘word clouds’ give a quick idea of the contents of some of my datasets. Wordle is an app that generates such clouds: the relevant text is fed into the app and the outcome is a nebulous collection of words that condense in such a way that the most important or frequently used keywords are rendered most eye-catching in the final cloud. So, if I was to round up all the records from the Historic Environment Record database that refer to prehistoric sites, features and finds… I would end up with a cloud like the black one below. It’s interesting that the word ‘field’ features comparatively prominently in this cloud, giving an indication of the importance of the field systems among the other recorded prehistoric sites. It is also somewhat telling that, when the text of the records relating to the prehistoric field systems alone is used (bottom), ‘unknown’ is one of the larger words.

Fig. 3 Word cloud representing the contents of the ‘prehistoric’ HER records. ‘Field’ appears centre-bottom, right and centre.

Word cloud representing the contents of the ‘prehistoric’ HER records. ‘Field’ appears centre-bottom, right and centre.

Word cloud representing the contents of the ‘prehistoric field system’ records from the HER. Note the relative prominence of the keyword ‘unknown’!

Word cloud representing the contents of the ‘prehistoric field system’ records from the HER. Note the relative prominence of the keyword ‘unknown’!

Data and Deliberations: Part 1

This is the part of the project where, having acquired my datasets, I have been cleaning them and converting them into a format I can use in my GIS. This has been more longwinded than it sounds, and what follows is a bit fiddly, but it’s a crucial part of the process. Don’t forget to click on the images to see bigger versions. The main datasets I have been wrestling with recently have been the Historic Environment Record database (kindly supplied by the National Park Authority), the National Mapping Pilot Project data (kindly supplied by English Heritage), lidar data (available from the Environment Agency) and aerial photographs (at the moment, I’m using a combination of prints from the HER and a layer available from ESRI that is similar to google maps). Historic Environment Record There are over 80 HERs in England, each of which contain details and records of the known archaeological sites, finds, interventions and surveys that have been recorded/have taken place within their area of jurisdiction – in this case, the Yorkshire Dales National Park. This makes them one of the major go-to sources for archaeological research. The Yorkshire Dales HER contains nearly 32,000 entries, the majority of which contain details including location and interpretation, and can be searched by various categories. But while the database is a mine of information, there are the inevitable limitations: for example, it has been compiled by numerous people over the years, resulting in a plethora of conventions and standards.

Fig. 1 Each of the red dots on this map of the Yorkshire Dales represents one of the 32,000 records from the HER.

Fig. 1 Each of the red dots on this map of the Yorkshire Dales represents one of the 32,000 records from the HER.

Obviously the records pertaining directly to the individual field systems are of interest, but so is the rest of the database – it provides a useful context against which to examine the field systems, acting as a background view of the prehistoric landscape. Fig. 1 shows the ‘raw’ data with each separate record represented by a dot. The distribution is interesting: the majority of known archaeological sites and findspots cluster in the valleys, with more white space visible on the higher ground – is this a real distribution of past human activity, or a reflection of present activity happening away from the less hospitable peat covered moorland where archaeology-spotting is more challenging?

Fig. 2 Prehistoric features and finds from the HER.

Fig. 2 Prehistoric features and finds from the HER.

So the first step was to sort the individual records into broad chronological phases, based on the ‘from’ and ‘to’ fields that have been filled according to the interpretation of the inputter. These can be selected from a ‘thesaurus’ of terms, such as ‘Late Iron Age’, so there is a reasonable degree of uniformity, but there is also a spectacular number of different combinations, making life difficult for me. I went for the low-tech approach and, with the help of the ‘find’ function in Excel, removed records for all those sites of unknown date and later-than-prehistoric origin. And then the remainder were broadly categorized into Early Prehistoric, Late Prehistoric and Prehistoric as it was felt that the majority of the features could not be accurately dated more narrowly than this. Their distribution is shown in fig. 2 below. National Mapping Project   The NMP dataset is a body of data that dates from the 1990s. It was collected as part of a project conducted by the Royal Commission on Historic Monuments of England with the aim of identifying visible archaeology from aerial photos: the Yorkshire Dales served as a pilot project to assess the effectiveness of the method over uplands. Aerial photographs from the Dales were transcribed, and recognizable features recorded with the use of a system of symbols. As it was done with pen and paper it has since been scanned to produce a digital copy.

Fig. 5 A tile of data from the National Mapping Project. The dotted areas with arrows represent ridge and furrow, the solid lines mark lynchets. The crosses are grid reference points.

Fig. 3 A tile of data from the National Mapping Project. The dotted areas with arrows represent ridge and furrow, the solid lines mark lynchets. The crosses are grid reference points.

When faced with a national park-worth of this data (fig. 3 shows how it arrived), it is quite overwhelming and difficult to work out what’s going on. It arrived as a set of raster files, so the first step was to vectorize it to make it possible to select each symbol individually. This also allows the removal of any smudges, grid reference points or paper ‘edges’ that are not real features. Then it was just a case of assigning each polygon to an appropriate layer category using AutoCAD. When I say ‘just…’, it was actually very fiddly and time consuming, but as a result I have a series of useful, colour-coded layers to add to the GIS (fig. 4).

Fig. 6 An area of NMP data near Kettlewell. The dark green polygons are features interpreted as field boundaries and lynchets; light green represents ridge and furrow; brown dotted lines are tracks; brown represents buildings.

Fig. 4 An area of NMP data near Kettlewell. The dark green polygons are features interpreted as field boundaries and lynchets; light green represents ridge and furrow; brown dotted lines are tracks; brown represents buildings.

It is not possible to assign dates to the features in the NMP data but it was possible to assign them to broad categories that cover, for example, evidence of extraction industries, ridge and furrow, settlement, and lynchets and field boundaries. Of course, some of those field boundaries belong to prehistoric field systems; the aerial perspective makes them relatively easy to identify (much more so than on the ground). The NMP report (Horne & McLeod 1995) identifies at least 35 prehistoric coaxial field systems. These are shown in fig. 5, alongside those known from the HER data (with varying degrees of confidence), and it is clear that there are already some overlaps and underlaps between the datasets. The NMP dataset in particular gives good coverage of the landscape as a whole, and will, for example, help to explain ‘gaps’ between recorded field systems where more recent ridge and furrow or lead mining is present.

Fig. 7 Comparison of field systems as identified in the HER and NMP datasets.

Fig. 5 Comparison of field systems as identified in the HER and NMP datasets.

One of the main reasons for going through these datasets so thoroughly by hand is that I am now much more familiar with the data. I have moved on to processing the lidar data that exists for the Park – more about that next time… Horne, P. & McLeod, D. 1995. The Yorkshire Dales Mapping Project. A report for the National Mapping Programme. Air Photography Unit: Royal Commission on Historic Monuments of England.

Visualizing the prehistoric landscape

Conveniently for me, my dad is a graphic designer. Also conveniently for me, he is retired and can be persuaded that he has time on his hands to apply some of his skills to his daughter’s phd project… hence the image below, which I hope gives some indication of what the landscape at Conistone Dib, Wharfedale, may have looked like in use in late prehistory. It’s a combination of dad’s illustration and my photograph, and is based on the archaeology and geomorphology of the area that is coming into focus in this project.

“Oh no, it’s crow stew again for tea”. Two iron age kids entertain themselves while the grown ups look after the animals. Illustration: Bryan Brown.

“Oh no, it’s crow stew again for tea”. Two iron age kids entertain themselves while the grown ups look after the animals. Illustration: Bryan Brown.

Conference life

One of the definite perks of phd life is the chance to go to various conferences, meet other researchers, compare notes, get feed back on your project and, of course, experience the local sights and sounds. This month, two relevant conferences came along at once – the annual meeting of the European Association of Archaeologists, held in Istanbul 10th-14th September, and the 3rd Landscape Archaeology Conference, held in Rome from 17-20th September. It’s a really tough life, being a phd student!

The Istanbul meeting was a large-scale affair, with over 3000 attendees from all over the world and numerous parallel academic sessions. I gave a paper in an interesting session on Comparative Perspectives on Iron Age Landscapes, which was intended to juxtapose various projects and methodologies from across Europe and subjects ranged from architectural monumentality in Mallorca, to woodland in Anatolia, cultural landscapes of French oppida and the Northumbrian landscape. My paper was nothing particularly ground breaking – an introduction to the Dales and their archaeology, and an overview of the data collection phase of the project and some of my suspicions – but there were some useful questions and in the subsequent coffee break I chatted to several very interesting people, and was introduced to a couple of new-to-me coaxial field systems (in Lincolnshire and Hertfordshire) that may well prove useful comparisons.

The Landscape Archaeology Conference in Rome was a much more modest affair, but equally stimulating. On the whole, it was quite biased towards Italian, Dutch and German research; it’s always intriguing to see what is going on elsewhere, and sessions ranged from ‘archaeomorphology as landscape archaeology’ and ‘integrated approaches in landscape archaeology’ to ‘computational modelling in landscape archaeology’ and ‘methodological approaches to social landscapes’. I presented a poster and the poster session was definitely one of the highlights – held alfresco with coffee and fresh peaches!

Let’s go fly a kite…

Over the summer there have been a few days in Wharfedale with just the right amount of wind to lift a kite without ripping it to shreds. And on some of those, I have managed to get out and about and take some more pictures with the camera rig that the lovely John Wells at West Lothian Archaeology has provided. These images are still somewhat experimental, but some of the results are here – the individual pictures have been stitched together by hand using ArcGIS in order to get a feel of the surface archaeology with more detail than is visible on aerial photographs taken from a higher level. The problem still remains, however, that the field systems are whole landscapes rather than individual sites and as such are difficult to photograph satisfactorily ‘in one go’.

Prehistoric enclosures below the scree of the scar line at Conistone (north is down).

Prehistoric enclosures below the scree of the scar line at Conistone (north is down).

Prehistoric enclosures and field boundaries below the scar line at Conistone (north is up). Some of the coaxial boundaries are visible on the bottom left and far right of the image.

Prehistoric enclosures and field boundaries below the scar line at Conistone (north is up). Some of the coaxial boundaries are visible on the bottom left and far right of the image.

Scar line (bottom) and limestone pavement at Conistone. A couple of the coaxial boundaries are visible continuing over the scar towards the pavement - the fact that boundaries continue across the pavement suggests it was originally vegetation-covered and has since been subject to processes of erosion.

Scar line (bottom) and limestone pavement at Conistone. A couple of the coaxial boundaries are visible continuing over the scar towards the pavement – the fact that boundaries continue across the pavement suggests it was originally vegetation-covered and has since been subject to processes of erosion.

Diversions

I have been branching out of prehistory lately and following a number of temporary diversions from my research, so I thought I’d tell you about them. As part of my placement with the Yorkshire Dales National Park Authority I have been able to get out and about and help with geophysical surveys done by some of the local archaeological groups.

 

Members of Ingleborough Archaeology Group use a magnetometer to survey the site at Selside.

Fig. 1 Members of Ingleborough Archaeology Group use a magnetometer to survey the site at Selside.

A section of the Selside magnetometer data (approx. 20m x 18m). The strong black and white anomaly towards the bottom left corner marks the position of a suspected hearth. The data is displayed at +/-2.75nT, black is high.

Fig. 2 A section of the Selside magnetometer data (approx. 20m x 18m). The strong black and white anomaly towards the bottom left corner marks the position of a suspected hearth. The data is displayed at +/-2.75nT, black is positive.

The first of these was Ingleborough Archaeology Group, who have been investigating a site on the hillside above Selside, Ribblesdale, which consists of the remains of several stone walled structures. The geophysical survey was used to give an indication of what might be there and, alongside other considerations, guide excavation strategy. Although the remains of the walls were visible on the ground as earthworks and rocks, they don’t show up in the magnetometer data (fig. 2) – they are made of the local limestone and, aided and abetted by the thin soils, have next to no magnetic contrast with their surroundings. The magnetometer did, however, detect several magnetic anomalies that I interpreted as being caused by hearths or similar burning, so it was encouraging to hear that subsequent excavation has revealed possible hearths. Excavation turned up very few finds, although this in itself, along with an early medieval knife, means that current thinking places the structures in the Pre-Conquest period.

 

I have also been involved with Swaledale and Arkengarthdale Archaeology Group and their geophysical survey of Ellerton Abbey, a scheduled site near Marrick, in Swaledale. The site contains the remains of a small Cistercian nunnery, probably founded around 1200. Only the ruined church survives above ground now, and this was the focus of architectural, earthwork and geophysical surveys in 1997, which investigated evidence for the surrounding priory complex – you can read the report here. Adjacent to the nunnery lies an area of earthworks believed to reflect a deserted medieval village, while the gill and hillside above the abbey are suspected of being the location of a mill and water management system; these (the DMV and mill/watersource) have been the subject of the latest magnetometer survey. The data is now at a processing stage and it will be interesting to see how interpretation of this complex site unfolds.

 

The site of Bainbridge 'univallate hillfort'.

Fig. 3 The site of Bainbridge ‘univallate hillfort’.

Resistivity data from Bainbridge, covering an area 20 x 40m. Data is displayed at +/-1 standard deviation, so black shows areas of high resistance and white represents low resistance i.e. ditches.

Fig. 4 Resistivity data from Bainbridge, covering an area 20 x 40m. Data is displayed at +/-1 standard deviation, so black shows areas of high resistance and white represents low resistance i.e. ditches.

The third expedition came about as part of a geophysics training day that I ran at the YDNPA office for interested local archaeology groups. After a session in the classroom, we carted the magnetometer and earth resistance kit up a small, nearby hillock (fig. 3). This hillock, overlooking Bainbridge’s well-known and conspicuous Roman fort, has a wonderful view over Wensleydale, a convenient position beside the River Bain and a pronounced ditch and slight bank encircling the plateau on the top. Unfortunately for the purposes of geophysical survey, this plateau is bisected by a large dry-stone wall topped with wire fencing, and several mature trees. The site is referred to in the HER as a probable ‘univallate hillfort’, although it seems this is purely on the strength of the earthworks, so besides being convenient, the site was also of potential archaeological interest. The participants did a great job of surveying half the internal area of the enclosure… and found the encircling ditch showing up well in the earth resistance data (fig. 4), with nothing in the way of internal features in the magnetometer data. With any luck, the other half will be surveyed shortly, but in the meantime it looks like the best interpretation might be as a stock enclosure!

 

Part of the magnetometer data from Giggleswick. The suspected training trenches show up clearly as the pale zigzag (though there also appear to be some positive anomalies associated with the structure). Strong, discrete black and white anomalies indicate responses to ferrous sources. Data displayed at +/-5nT, black positive; area approx. 40 x 20m.

Fig. 5 Part of the magnetometer data from Giggleswick. The suspected training trenches show up clearly as the pale zigzag (though there also appear to be some positive anomalies associated with the structure). Strong, discrete black and white anomalies indicate responses to ferrous sources. Data displayed at +/-5nT, black positive; area approx. 40 x 20m.

Most recently, as part of the YDNPA Training and Trenches project, a survey of 2 suspected WWI training trenches was undertaken. The trenches, on the hillside overlooking Giggleswick School, Craven, may have been dug and used by the school’s Officer Training Corps. Alongside building survey of the Drill Hall at Settle, and earthwork survey of the firing range at Attermire Scar, the trench site was previously subjected to plane table survey by eager volunteers. Poor site conditions mean that the magnetometer data (fig. 5) isn’t as good as it could be, but it is certainly good enough to locate the suspected trenches – the well defined white zig-zags! It is interesting as, rather than having been backfilled with magnetically noisy rubble, they have been detected as less magnetic than the surrounding soil – perhaps containing wooden shoring or voids? Whereas in most archaeological geophysical surveys the strong ferrous signals (the discrete, black and white blobs!) would be considered as modern debris and therefore interference, in this situation they may well represent bits of the relevant archaeology that we are looking for. As part of the project, the trenches are being excavated in late June 2014, which will provide a great opportunity to compare the archaeological record with the geophysical results…DSC_1042 copy 2

Up, up and away…

Aerial photographs are one of the most important sources available to archaeologists. Following the use of aircraft for military reconnaissance in WWI, the use of aerial photographs for other purposes – including spotting archaeology – really began to take off (so to speak).

 

One of the most important exponents of archaeological aerial photography was O.G.S. Crawford, who took a notably modern approach to the study of archaeology. Crawford was a contemporary of E. Curwen, who independently recognised the early field systems that Crawford referred to as ‘Celtic fields’. Importantly, Crawford was not just interested in ‘spotting old things for their own sake’, but in using aerial photographs to recognise and interpret patterns in the archaeology. In a 1923 lecture he demonstrated how he had used aerial photographs to accurately map the distribution of Celtic and Saxon settlements on Salisbury Plain; from this, he could show complex layers of occupation that were not visible on the ground, and indicate broader transitions that had taken place (Crawford 1923). The benefits of an ‘integrated’ approach is a recurring theme throughout Crawford’s work – long before it became a 21st century buzzword – and he regularly emphasized the use of aerial photography in conjunction with excavation and other sources.

 

The Yorkshire Dales National Park Authority has a comprehensive collection of aerial photographs that will help to define the extent, context and relationships of the coaxial field systems. But more on these at a later date…

The beginnings of aerial photography, however, go back before the use of aeroplanes, to the late 19th and early 20th centuries when kites of assorted designs were developed to carry camera rigs, to capture meteorological, archaeological and news reporting images, amongst other investigations. Kite Aerial Photography has been used since – see, for example, some fantastic pictures from the Scottish National Aerial Photography Scheme (SNAPS) here.

 

I was recently given a camera rig by the lovely people at SNAPS and have been attempting to do it justice. Unfortunately, the weather here has not been very cooperative lately (or breezy, which is hard to believe in the Yorkshire Dales), but I have managed to collect my first few pictures: they certainly suffer from the effect of the overcast sky, but they give an impression of the potential for providing detail and context for the prehistoric remains.

Field system near Conistone, looking towards Grassington. Coaxial boundaries are visible running down the slope from the left hand side of the photograph, either side of the modern boundary wall. © H. Brown.

Field system near Conistone, looking towards Grassington. Coaxial boundaries are visible running down the slope from the left hand side of the photograph, either side of the modern boundary wall. © H. Brown.

Near Conistone. Two coaxial boundaries cross the Dales Way footpath. The kite operator, walking along the tope edge of the photo, provides a sense of scale. © H. Brown.

Near Conistone. Two coaxial boundaries cross the Dales Way footpath. The kite operator, walking along the tope edge of the photo, provides a sense of scale. © H. Brown.

It turns out, sheep really like kites. © H. Brown.

It turns out, sheep really like kites. © H. Brown.

 

References

Crawford, O.G.S. 1923. Air survey and archaeology. Geographical Journal, May: 324-366.

Research trip: Céide Fields, Co. Mayo

Uncovered neolithic field wall at Cíede (with the visitor centre and North Atlantic in the background). © H. Brown

Uncovered neolithic field wall at Cíede (with the visitor centre and North Atlantic in the background). © H. Brown

In October 2013 I made a trip to County Mayo, northwest Ireland, ostensibly to visit friends, but also to visit the Céide Fields visitor centre. Céide has a wonderfully extensive landscape of prehistoric coaxial field systems, which has been preserved so effectively by several metres of peat and blanket bog that have developed on top of them. Field walls were first unearthed in the 1930s by the local school teacher, Patrick Caulfield, as he was digging peat in his garden in Belderrig, 7km west of Céide. Years later, his son, Seamus, went on to become an archaeologist (and eventually professor) and returned to investigate the Belderrig and Céide field systems (Caulfield 1978, 1998). Years of research ensued, which included tracing the lines of the field boundaries for kilometres under the peat by using an iron rod to probe the ground: when the metal rod is driven into the soft peat, the operator can feel whether or not there is a stone boundary at the bottom which can then be mapped to reveal walls, buildings and tombs.

Probing for field walls: the metal probe is used to detect their presence and the bamboo canes measure the depth of the peat. © H. Brown

Probing for field walls: the metal probe is used to detect their presence and the bamboo canes measure the depth of the peat. © H. Brown

Over the years more than a thousand hectares of fields have been traced in this way, revealing an expansive managed landscape. Radiocarbon and pollen dates obtained from materials across the site indicate that the field systems were already abandoned and covered in peat by 2500BC (Caulfield 1998) making them the earliest known field systems of this type in the world. The remains of the walls – which must contain many thousands of tons of stone – indicate a coherent and structured Neolithic society, with sufficient labour resources to clear woodland, divide up and maintain the land in an organised manner. The large area and extent of the fields suggest they were used for pastoral farming, although the team have discovered some early plough marks in the vicinity of settlement.

Roots of the c.5000 year-old scots pine preserved in peat, now taking pride of place in the visitors' centre. © H. Brown

Roots of the c.5000 year-old scots pine preserved in peat, now taking pride of place in the visitors’ centre. © H. Brown

All this is particularly interesting in the light of the Yorkshire Dales field systems, given that the Irish examples appear so similar in form yet date several thousand years earlier than the presumed date of their Bronze/Iron Age Yorkshire counterparts.

The arrangement of archaeology and visitors’ centre at Céide is fantastic – definitely a lesson in presenting ancient archaeological landscapes that could potentially be so uninspiring. The undertaking comes under the jurisdiction of the Office of Public Works and appears to be a success, attracting numerous visitors in a location where it is very difficult to be ‘just passing’. The centre itself is a striking pyramid cut into the blanket bog; inside, it is built around a large, gnarled scots pine tree trunk, around 5000 years old, that was preserved in the local peat.

One of the most notable aspects of the Céide visitor centre is the emphasis that is put on the field systems as a landscape, as opposed to just a site. This is underlined by the large proportion of the exhibition that is dedicated to the regional geology, geography and the local formation of peat and blanket bog. The exhibitions spiral up to the top of the building, where a viewing gallery (incorporating a glass-covered all-weather option – this is Ireland, after all) affords extensive views over the centre and beyond, placing the fields firmly in the context of the dramatic cliffs and expansive panoramas of the north Mayo coast. Definitely worth a visit!

References

Caulfield, S. 1978. Neolithic fields: the Irish evidence. In Bowen, HC & Fowler, PJ (eds) Early land allotment in the British Isles. A survey of recent work: 137-144. British Archaeological Reports 48. Oxford: Archaeopress.

 Caulfield, S. 1983 The Neolithic settlement of North Connaught. In Reeves-Smyth, T & Hammond, F (eds) Landscape Archaeology in Ireland: 195-215. British Archaeological Reports 116. Oxford: Archaeopress.

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© H. Brown

© H. Brown