A day-by-day account of the activities of the Rossnaree Archaeological Project 2010-11

Posts tagged “archaeological techniques

Day 19 – It is all becoming clear now…

First of all, the piece that RTE came to the site to film was aired on the 6-One News and the 9 O’Clock News on RTE1 last night. It is amazing how much time was spent on-site and how much footage was shot to make up the final piece. I think the point was well made, however and thanks to Chris in the Institute of Archaeologists of Ireland (IAI)  for setting up the piece and to Philip Bromwell for his interest and patience. For those who didn’t see the piece, the link is:

http://www.rte.ie/news/av/2011/0727/media-3012820.html
Cut 8 cleared at last!

Anyway, back to business at Rossnaree. There was prolonged rain overnight which thankfully had cleared by morning. This moisture did wonders in each of the cuttings because suddenly there was, once again, some colour in the soils. Instead of a continuous hard-packed dusty pale yellow surface like concrete, we could see all shades of brown, orange, yellow and even red. At last we had some clarity and we able to distinguish between the last skims of ploughsoil and the undisturbed natural. If only this had happened a week ago it would have been much more helpful, especially in Cuttings 7 and 8 where had such difficulty. That’s the way the breaks come – all real discoveries inevitably seem to come in the final week of the dig (remember what happened last year!) or, worse in the last day or two.

Sieezing the opportunity presented by the conditions, Darren, Sophie and Ciara trowelled over the surface of Cutting 8 one last time to reveal a number of disturbed areas which are probably the remains of additional graves in the cemetery. At this late stage of the dig it is not feasible to excavate further but we at least have been able to identify and record the location accurately. All of the new detail was added to a plan of the cutting later on that afternoon.

Kieran to the rescue!
Matt planning again.

In Cutting 7 we were joined by Rossnaree veteran Kieran Campbell who was a member of the team from last season. Kieran very kindly offered to help out in the last few days of the dig – exactly the time when he is needed most. Kieran undertook to lift the skeleton in Burial 2 along with Matt. Mags recorded a number of the features that Matt had previously examined in the cutting by drawing sections and profiles of them. Matt later finished drawing the post-excavation plan of the cutting and he added the detail of the grave cuts. When this was done he drew up the southern section face of the cutting showing the depth of ploughsoil and the various levels within it. Kevin was also on hand again today and using a total station he accurately recorded the positions of the control points we had installed around Burial 2. He also surveyed in the location and shape of each of the grave cuts of Burials 1 and 2.

In Cutting 6 Eimear carried out post-excavation plans of the two completed sections and also drew up the profiles of the sides of the cuttings. Niamh continued to excavate a section through the oval enclosure ditch and this is turning out to be quite a substantial feature. It is a lot deeper and wider than we had anticipated but she has found the edges on either side as well as the base. Very good work for one day.

Tomorrow, we will finish the last of the recording and then start the backfilling. I’ll let you know how we get on.

Nearly there…

Day 16 – The pressure’s on.

We are now into the final week and there seems like so much still to be done. At least the weather is holding up. It was not as sunny as it was over the week end – the day started out a bit overcast with a few drops of rain as well, but very calm. As the day wore on the cloud cover thinned and although the sun didn’t come out fully it was quite a warm and pleasant day.

Mags and Ciara in Cutting 7

In Cutting 7 Lisa and Ciara continued the final clean-down of the surface to make absolutely sure that there are no further features there. Matt started work on lifting a piece of cranium we had noticed on Friday in the south west corner of the cutting, a little distance away from the grave cut. We had assumed that this was a fragment of bone disturbed from another grave but as Matt cleared more it became apparent that there were several pieces of bone in situ within the fill of yet another grave cut. This, of course, is not surprising because we already have found one grave, but it is not something we had planned, or hoped, to find. The work in this area will now slow down again considerably as the grave is carefully excavated and recorded. This is time we can’t really afford at this late stage.

Human bone fragments and another grave cut.

Matt bags up some of the bone.

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Darren working on his section.

Eimear's ditch section today.

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In Cutting 6 Eimear and Darren continued work on their respective sections and both were successful today in finding the western edges of the cut. In each case the edge was cut into quite gravelly material, very similar to that identified in the base of the ditches excavated last year. Ash, animal bone and charcoal are all frequent and at Darren’s end, there seems to be a lot of flint while at Eimear’s end there is an interesting socketed iron object, probably a tool of some sort, sticking out of one of the layers. Kevin had identified this as a location of some potential last week when he scanned the cutting surface with his metal detector. The next step is to identify the various fills visible in the vertical section face of each mini-cut and then to photograph and draw them up.

In other news, we had a visitor today from RTE television – Philip Bromwell – who is doing a piece on how the archaeological profession in Ireland is faring in the current recession. This was a suggestion made by the professional body for archaeologists in Ireland, the Institute of Archaeologists of Ireland (IAI). As well as filming the dig in progress and speaking about the stages in the research process leading up to the excavation, there was discussion of the many archaeologists who had been working in the profession who are now unemployed. There was also some talk about the severe cuts in various research funds available for archaeological research like the Heritage Council’s discontinued Heritage Research grants or the INSTAR grants. The piece will hopefully air on the 6 One News later this week. I’ll let you know…!


Day 15 – Summer’s back!

Well, who’d have thought it? Met Eireann, the Irish weather service issued an apology for the weather forecast for yesterday. They said there’d be occasional showers in the east of the country (where the Rossnaree excavation is located) but instead there was virtually continuous grey wet drizzle for much of the day. You have to take the rough with the smooth – normally when the forecast suggests that there might be showers or rain, I have found that we have a good chance of being lucky. The rain takes a little bit longer to get across the country to us in Rossnaree and we usually seem to escape the worst of it. To have the opposite happen once is, I think, acceptable because of the number of escapes we have had over the last few weeks.

Ciara cleans Cutting 7.
Excavating the human remains.

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The weather on-site was perfect – bright spells and cloud, not too hot, and no rain of any sort. Everyone was in a good mood (I think) and there was an air of quiet industry over the site for much of the day. Ciara was working single-handedly in Cutting 7 for the morning giving one last clean-back to the exposed surface there to make sure that no possible features had been missed. After lunch, Matt did a plan of the grave again, detailing the position of each of the bones and we spent the afternoon excavating, lifting and carefully packaging each bone. Each piece was numbered on the plan and photographed and wrapped and labelled for storage and later study.

Mags and Sophie clean back Cutting 8.

Mags and Sophie continued to take down the last of the disturbed layer of soil overlying natural in Cutting 8. Despite the rain the previous day, the soil was drying out very quickly making the identification of the different colours difficult. The layer closest to natural has quite a mottled appearance – it is a mix between the compact yellowish natural and ploughsoil and has frequent worm holes through it. There are still occasional flecks of charcoal and occasional fragments of bone so we are certain that the surface is definitely not natural. Hopefully we will be finished in this cutting very soon.

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The needle in situ.
Eimear displays the needle.

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In Cutting 6 Eimear continued to dig the section at the southern end of the cutting and a number of interesting finds came up. Below the upper layer of charcoal rich soil there is a thick deposit of almost pure ash and within this there is a deposit of animal bone, probably cow, including a mandible (jaw) and rib, among others. These seem to have been deliberately deposited with a number of burnt stones (one of which Eimear named ‘the raspberry stone’ because of it’s vivid colour!) and also an intact bone needle/pin. This is definitely find of the week and although it can’t be closely dated, it definitely belongs to the early medieval period. The Neolithic remains elusive.

Darren’s ditch section so far.

We set Darren up at the northern end of the cutting doing a similar section to Eimear across the ditch. We seem to have clear edges to the ditch feature with natural visible on both sides. Again, the fill is very rich in charcoal and ash and the edge of the cut of the ditch is quite steep. There was still no sign of the base of the ditch cut in the evening when we were finishing up. Flint artefacts were frequent but it is not clear whether they are indicating a date for the digging of the ditch or whether they were disturbed and incorporated into the fill of the ditch during the early medieval period. Lots to look forward to on Monday.


Day 11 – A new week.

Igor tests his trowel.

We’re over the half-way mark now and beginning to think about making sure we are able to finish everything we start in the time available. We were joined by a new person this morning for a few days – Igor – who was involved in the geophysical surveys of each of the areas immediately prior to the start of the excavation. While Igor now works mainly in geophysical surveying, he has spent time on a number of the Celtic Tiger road schemes and his experience is welcome.

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Matt and the ‘mystery feature’.

The weather over the week-end had been quite mixed with a lot of showers. This was good for the site because when we arrived down and took a closer look at the cuttings, the additional moisture in the soil has made it a bit easier to see the differences in the colours and textures of the soils making up the fills of features. In Area 2 Matt continued to examine features that were identified and planned last week. He did this by half-sectioning them. This is where half of the feature is excavated using a trowel or a leaf trowel to find the exact extent and the cut and base of the feature before excavating and removing the second half. This usually means that the excavation of the second half of the feature is more accurate and ensures that any soil samples, which are only taken at this stage, are less likely to be contaminated with other soils. These soil samples can later be processed to identify macrofossil remains, i.e., fragments of vegetation etc. which, in turn, can tell us about the environment around the site at the time the feature was in use.

Most of the features that we had identified turned out to be less than exciting. Many seem to be pockets of soil that had accumulated in deeper-than-usual hollows left in the subsoil where large cobbles were disturbed by ploughing. However, there is one area where there may be a substantial feature containing a number of fragments of bone. We have labelled this Feature 714 and we will take a closer look tomorrow before coming to any conclusions. I’ll keep you posted.

Darren ‘The Machine’!
Sophie on the sieve (again!).

Darren and Sophie continued to take down the ploughsoil in Cutting 8 and this was almost completed by finishing up time after a burst of very robust mattocking by Igor. Once the cutting clear, we will work it back again to find the base of ploughsoil in the same way as we did in the other cuttings. However, this process should be a lot quicker this time because we have a very good feel for what the local subsoil looks like and at what depth we should expect to find it.

Eimear’s the boss!
Area 1: ‘you could eat your dinner off it!’

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In Area 1 the cleanback continued in preparation for photographs and planning. The whole surface of the cutting had to be troweled over lightly again because a certain amount of dust and other debris had blown in over the week-end and the rain had made the surface less clear and distinct. Eimear was in charge and by the afternoon, the photos were taken and the planning could begin.


Day 6 – Moving up a gear.

Magnetic gradiometry, Area 1.

We all arrived down to the site hut revitalised, reinvigorated and ready for the new week. We were close to being completely free of the monotony of mattocking, shoveling and sieving through ploughsoil, although the finds we are coming across are nice. In Area 1 at the start of the day there were still 10 square metres to be dug away and throughout the day the team there got through seven and two half squares. Tomorrow, there are only two half-squares and one full one to go. Once they are gone, we will be nearly ready to begin to search for the features identified in the geophysical surveys carried out by Kevin before the dig started up. In the plot the cutting itself is made up of columns G, H and I and extends from row 1 to row 10. This takes in two very distinct features: one, a possible ditch running from north to south (from previous geophysical surveys this seems to be the innermost enclosure defining the knoll of high ground) and the second, at a higher level and cutting the other feature curving in from the middle of the right side to the bottom of the panel (this seems to be a separate oval enclosure superimposed on the other ditch. See the original plot HERE). This cutting will investigate the exact relationship between these two separate features and hopefully will yield material for dating.

Lisa, Mags and Sarah.
Sophie on the sieve.
Darren gets to trowel.
Magnetic gradiometry, Area 2.

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In Area 2, they started the day with just two metre squares to go and these were quickly removed and sieved. Once this was completed, we took another series of soil samples for lab magnetic susceptibility measurements using the same grid as before. Thus we will be able to compare values taken from the field surface to those at the base of ploughsoil. Once this was done the cutting was ready to be troweled back. There was still a layer of ploughsoil over the cutting – we deliberately didn’t remove everything when we were mattocking off the ploughsoil partly to protect the site from being open too long and from the impact of people crossing over and back as they work. Trowelling, with the help of some light mattocking where necessary, is the next step taken to remove any remaining layer of disturbed ploughsoil and begin to identify the features underneath. We are lucky in that we have a very detailed set of geophysical plots to guide us as to what to expect. However, the picture here is less clear with a series of features that are unfortunately less identifiable than those in Area 1. The excavation here is to explore the nature of these possible features – our hunch is that they may be houses because of their location within the innermost enclosure on the highest point in the site – but we will be scratching our heads if we don’t end up finding the features indicated on the geophysical plots. The cutting itself measures 5m x 4m and is located between squares Q10-13 and U10-13 although this will probably be extended southwards at a later stage.

Eimear searches for the feature in square U13.
All hard at work in Area 2.

Day 2 – Now the digging begins

Matt cuts the first sod of the season.

Having successfully taken all of the soil samples from the ploughsoil surface for later magnetic susceptibility analysis there was nothing further to delay actually getting stuck in and doing some digging. We set out each cutting – Cutting 6 in Area 1 and Cutting 7 in Area 2. We are continuing the trench numbering system from last year to avoid any overlay or confusion in the archive. Cutting 6 measures 10m x 3m and is orientated north-south while Cutting 7 measures 5m x 4m.

An interesting find turns up in the sieve.

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The ploughsoil in each cutting is being taken down first using mattocks and shovels and the spoil is being sieved for artefacts. This is being done on a metre-by-metre basis so there is spatial control on the artefacts retrieved. Although the ploughsoil is a disturbed context and a very dynamic layer, there could be a relationship between the material ‘floating’ in the ploughsoil and the features beneath it. We are recording the spatial locations of the artefacts anyway and hopefully in the final analysis patterns and relationships will emerge.

The Area 2 sieve

Mags and Jamie using the Area 1 sieve.


Geophysical Survey 2010

Following the surprise development in the excavation last year where it was conclusively established that the enclosures on the site are likely to be early medieval in date (and probably between 7th-11th century AD), it was decided to carry out further geophysical survey over the core area of the site on the top of the knoll within the tillage field. This was clearly a focus of activity in prehistoric times because of the extensive lithic (flint) scatter found there. It also seems to have been a focus during the early medieval period as this is the area central to all of the enclosures.

Because of the lithic scatter, this area remained the best candidate area for identifying prehistoric activity. However, because of the apparent intensity of activity in the early medieval period, there is a chance that any prehistoric features that may once have existed are completely destroyed and disturbed.

With these problems in mind, a second programme of geophysical survey was carried out in August 2010 at a higher resolution than the original geophysical surveys. The hope was to identify more clearly any features that might be earlier than the early medieval enclosures. Three high resloution surveys were carried out: magnetic gradiometry (Figure 1), earth resistance (Figure 2) and magnetic susceptibility (Figure 3). See the following figures for the results of each of these.

Figure 1: Detailed magnetic gradiometry plot with topography, August 2010

The magnetic gradiometry has shown up more detail than was apparent on the original survey. For example, the second enclosure from the outside clearly deviates from its curvilinear path as we move northwards towards the terrace slope. This may be a modification of an earlier version of the enclosure as there are hints of an earlier, less definite enclosure continuing northwards. The other feature of interest is the relationship between the inner complete oval enclosure and the D-shaped enclosure beneath it. The oval enclosure looks like it cuts through the other enclosure and thus is later in date. Furthermore, there is a difference in the quality of the magnetic response between the two features suggesting that they are constructed differently. The oval enclosure is more similar in the character of its response to the other, outer, enclosures. There seems to be a contrast between the innermost D-shaped enclosure and the rest of the enclosures, possibly suggesting different construction techniques which may be due to their being constructed at different dates. Clearly, the innermost D-shaped enclosure is earlier than the oval one. The question is how much earlier. Are we looking at a possible prehistoric enclosure?

Figure 2: Detailed earth resistance plot with topography, August 2010

The contrast between the different enclosures noticed in the magnetic gradiometry is replicated to some degree in the earth resistance plot in Figure 2 so what we are seeing is likely to be real and reflect the real character of the features themselves. The innermost D-shaped enclosure is almost invisible on this plot, especially along its western side. At the southern end of this inner enclosure feature there is an area of high resistance with a sharp delineation between the high-resistance (light coloured in the plot above) inner area and the low resistance area immediately outside (dark coloured). The junction between the two areas appears to be particularly sharp and suggests a possible stone facing/revetment feature.

Figure 3: Detailed magnetic susceptibility plot with topography, August 2010

The magnetic susceptibility plot shows an area where the soils have been strongly altered by activities like burning and the disposal of organic waste. It shows a clear and distinct focus of activity which seems to be contained to the west by the third enclosure from the edge. It extends a lot further to the south than the line of this ditch and continues on outside the survey area. There is a band of low values running in a north-south direction through the middle of the zone of enhancement which may be due to the way the space was utilised in the past, or it may be due to sampling or post-depositional processes. There seems to be a slightly separate elongated area of enhancement running east-west along the northern boundary of the field which may be a secondary activity focus. It may be significant that this is focused on the southern side of the highest point of the topographic knoll.


2010 Season Report

This interim report describes the work undertaken during the 2010 excavation season at Rossnaree Co. Meath. The excavation took place over a four-week period between Monday 5th July and Friday 30th July and targeted a series of topographical and geophysical anomalies identified in previous survey work. The site was first discovered as a dense scatter of lithic (chipped stone) artefacts systematically recovered from the surface of a tilled field during a major extensive surface collection undertaken some years previously in the Brú na Bóinne area (National Museum of Ireland collection number C97.2).

magnetic gradiometry survey Rossnaree Excavation

Mark carrying out the magnetic gradiometry survey

Subsequent multi-method geophysical survey funded by the Heritage Council and undertaken by Kevin Barton of Landscape and Geophysical Services revealed the presence of a large multi-vallate enclosure on the banks of the River Boyne which is roughly D-shaped and is bounded on the north and east sited by the River Boyne at the point where the famous ‘Bend of the Boyne’ begins. The enclosure cordons off an area of approximately 3.5 hectares and measures c.250m east-west by c. 150m north-south. This enclosure was reported to the Archaeological Survey of Ireland and an RMP number was subsequently issued (ME019-080—).

Excavation funding was granted for a dig in 2010 by the Royal Irish Academy Committee for Archaeology and four trenches in total were opened and excavated during the season. Two of these trenches focused on extant low bank-and-ditch features located to the north of the tillage field close to the riverbank. A third trench (Trench 4) examined the continuation of the line of the outer enclosure in the low floodplain to the east of the core area of the site and a fourth trench (Trench 5) investigated the area around a semi-buried greywacke slab close to the field boundary in the pasture field to the east of the core area of the site.

While flint flakes and tools were frequently recovered, the major features on the site, especially the bank feature in Trench 3, was dated to the early medieval period on the basis of the recovery of a double-sided bone or antler comb fragment. A fragment of a copper-alloy strap was also recovered from the same context. A fragment of a lignite bracelet was also recovered from topsoil in Trrench 5, also indicative of activity during the early medieval period.

The interim report may be downloaded in PDF format here. Rossnaree_Report_2010(lowres)


Day 20: The longest day

Rossnaree excavtion Trench 3

Trench 3 fully filled...at last!

Once again, I am reduced to beginning a post by talking about the weather. Today was the last day of the dig and a lot of hard work lay in store for the small but elite group of diggers remaining on site. If desodding is regarded as an unpleasant job, backfilling is much more difficult and demoralising. To make matters worse, the weather was not kind to us today, making the job much more arduous. It started off drizzly, stopped for a while, started again, and so on until about three o’clock. Although we had completely backfilled Trench 4 already, there were still two, Trenches 1 and 3,  to backfill. These were going to be tougher than 4 because they were situated on a slope.

Rossnaree excavation Trench 3

Trench 3 spoilheap disappears

Because of the topography immediately around these trenches, there was no option at the beginning of the excavation but to place the spoilheaps for each of them downslope of the trenches. This meant that every bucketful of spoil dug out of each of these trenches had to be shovelled into wheelbarrows and barrowed back uphill. At Trench 3, this meant that a zig-zag route was required, lengthening each journey across the slippery slope surface. In spite of the challenging conditions, we eventually reached our goal and completely filled the trench.

Rossnaree excavation Trench 1

The Trench 1 spoilheap

Rossnaree excavation Trench 1

The team gets to work on Trench 1

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Then we moved on to Trench 4. A ‘closing deposit’ had been created on the top of the spoilheap by Clíodhna (age 6!), perhaps to appease the spirits of the place and atone for the disturbance that they had to endure over the previous four weeks. We worked until six, when we were fit to drop and a big thank you goes to all of the team who pitched in on this dreaded day lightening the workload with cheery conversation (and even some song!).

A big thank you goes to all who assisted with the excavation. Many people worked on the site over the few weeks, some longer than others. All time spent on the site helped and is greatly apprecated.

Rossnaree excavation Trench 1

The Trench 1 'closing deposit'

So to Matt, Kieran, Darren, Eimear, Niamh, Deirdre, Eamonn, Andrew, Valerie, Mark, Ailbhe, Michael, Gary, Jessica, Carol, Kim and Louise a very big thank-you. Thanks to Kevin and Mark for the surveying and the support and encouragement. To Paschal, thanks for facilitating our access to the field, to Fin and Steve for lending us the equipment we needed and helping with the logistics, to Niamh for the scones, to our visitors who took the time to come and see what was going on and also give their support, both moral and practical. And finally, to Aisling, many many thanks for allowing us access to one of the most enchanted corners of this island for the month.

Because the sitework is now finished, there will be no more day-by-day posts. However, we hope to do some additional ‘tidying up’ survey work soon in order to try to identify the presence of potential prehistoric features and I will post the progress and results of that work. Also, the post-excavation work will now commence, but as much of this will require additional funding which will hopefully be provided at a later stage, and there will be occasional posts on this as the work is done. Thanks to everyone who took the time to check out the blog; many of the comments came from people who are not known to me and who seem not to be archaeologists but who, nonetheless, found the blog interesting and informative.


Day 18: The devil is in the detail

Rossnaree excavation Trench 4

Eimear backfills Trench 4

Today, a very dramatic occurrence took place – Trench 4 disappeared. Seriously, we had completed all the necessary work in that trench and yesterday, Kieran had started to backfill. Today, this job was completed in fine style by Kieran, Eimear, Niamh and Darren. We were even able to replace the sods back on the top. In a few weeks, it will be like we weren’t there at all. It is a bit sore having to fill in after so much slow painstaking work, but that is the name of the game in research archaeology.

Replacing the sods

The final result.

Rossnaree excavation Trench 1

The team working hard in Trench 1

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Some very serious work was done in Trench 1 today by a very dedicated group of individuals. The first job was done by Louise who had yesterday discovered the pit-like feature at the south side of the trench. She drew a quick section of the feature and a plan as well. Once this was done, it was possible to start excavating again and although it had been decided not to excavate the full extent of the trench in order to save time, they went ahead and took out the remaining layers anyway. A fantastic piece of work. At this stage the final jobs to be done here are to draw the sections and take the samples. By the afternoon, Kim and Louise were setting up to start this so by tomorrow lunch time we should be ready to take samples. Things are moving very quickly!

Rossnaree excavation Trench 1

Kim draws the section in Trench 1

Meanwhile in Trench 1 Matt and Darren started off the morning cleaning up the lower portions of the feature they had uncovered yesterday. They were preparing for record photographs and also for planning and drawing the section. The feature itself is interesting because it seems to be at a lower level than the wall and thus is earlier in date. It seems to have functioned as a revetting feature which held the slope in place. The slope is composed of quite loose gravels and this may have caused problems for the inhabitants of the site who wanted a more stable slope. As I mentioned yesterday, there seem to be similar features peeping out from the grass in the slope further along from the trenches where we are digging. This cleaning was completed by mid-morning, after which Darren went to Trench 4 and Matt got going setting up for drawing the plan. While they were cleaning down onto this final level, a number of very interesting finds came up which throw a lot of light on the date of the activity in this area. Almost directly where the wall feature made of large cobbles had stood within the bank, they found a portion of a double-sided comb, possibly made of antler. This is little bigger than my thumbnail but is nonetheless very significant. Finds like these typically date to the eighth century AD or later (as far as I know – I’ll have to check this) and it tells us that the bank/wall (and probably the ditch beside it as well) must date to this time or a little bit later. This is clear dating evidence for the feature from excavation and means we don’t have to wait months for radiocarbon dating in order to find out what date this activity was.

Rossnaree excavation Trench 3

The revetment feature in Trench 3

A couple of other finds from this general period came up within hours – a small copper-alloy strap and a fragment of an iron vessel. Sometimes this is the way things work out in archaeology – you don’t get the crucial finds until almost the last minute. in spite of so much flint from these layers, it is now clear that the feature is Early Medieval. The flint was probably on site already and was incorporated into refuse material used by the Early Medieval occupants of the site and there is still no doubt that the site was intensively used in Neolithic times. We now also know that it was also used intensively in Early Medieval times as well. We have another multi-period site, a bit like how the site at Knowth across the river was used. The big questions now are are the other banks and ditches the same date and where are the structures that were used in prehistoric times.


Day 15: Friday fun day

Rossnaree Excavation: Stonehenge

Stonhenge, 2008

There has been a bit of coverage of a recent discovery of a low-visibility monument very close to Stonehenge. This was discovered during an intense geophysical survey of the area by English Heritage and is part of a survey that is planned to last three years. The site is interesting and, as they said themselves, it bodes very well for the rest of their work to have found a site so quickly.

You can view some of the BBC’s reports at this link: Stonehenge.

Reports of this discovery were carried on most of the UK national TV news programmes, and although this is the silly season, I can’t help wondering whether there is a difference in the attitudes to new archaeological discoveries in Britain and Ireland. Geophysical survey work like this has been going on over the past three years here in the Brú na Bóinne WHS, albeit on a smaller scale, which has received scant attention. By contrast, there has been a considerable amount of media interest in the excavation at Rossnaree, at least at a local level. It seems that in the public (or media) consciousness here, the work of archaeologists is perceived as digging holes in the ground and finding stuff. As followers of this blog (and others) will know, there is a lot more work involved in archaeology than just excavation.

We have sites just as good as what was discovered at Stonehenge the other day. Just by way of comparison, the new Stonehenge site is about 25m in diameter. The Rossnaree site is about ten times larger, measuring about 250m east-west and 200m north south. The archaeology of Brú na Bóinne and many other parts of our country are in no way lower quality or less interesting than that of Stonehenge or elsewhere and we (archaeologists and media) should be doing more to celebrate this rich and diverse aspect of our heritage. There is definitely scope for a Stonehenge-type geophysical survey project, similarly structured and resourced,  in the Brú na Bóinne WHS. This is work that really needs to be done for us to more fully understand how this very important landscape was used by past generations and also to more properly take stock of the archaeological resource of the area to inform its effective presentation and management.

Rossnaree Excavation Trench 4

The level is going down...

Anyway, back to the business of the Rossnaree excavation. We are really trying to schedule the remaining jobs to be done around the site at the moment as we look forward to our last week on site. The same work of the last few days continued in each trench. In Trench 1 Kieran, Eimear, Darren and Deirdre continued to take down and sample the levels in the ditch fill, sieving as they went. The extra manpower in this trench payed big dividends and a lot of progress was made. Just two more fills to be removed before the bottom is reached. Next week, to finish off the trench and shut it down, we will move into the western end to see how deep the stony surface is above natural. We suspect (and hope) that it is not too deep because we really don’t have time to get bogged down.

Rossnaree excavation Trench 1

Kevin and Deirdre speculate on the results

The ERT section suggests that there’s not too much depth in this area but we’ll just have to wait and see what turns up. We had a visit from Kevin the geophysicist again today who had a few jobs to do around the site. He is dropping back on a regular basis to see how the excavation progresses and also to see how well the excavation evidence matches up with the results of his earlier geophysical surveys. In Trenches 1 & 3 he is particularly ineterested in the match because the ERT line runs straight through the trenches we dug and should match up exactly. It is relatively rare that geophysical surveyors get to match up the results of their surveys with ‘reality’, i.e., the excavated layers themselves. These are the opportunities afforded by research excavation – the chance to experiment a bit and learn new ways of doing things.

Rossnaree Excavation ERT section

The ERT section with trench positions indicated

Rossnaree excavation Trench 4

Kevin takes samples from the Trench 4 section

Kevin also decided to take another series of soil samples from Trench 4 of very closely spaced intervals. Again, this is part of a research approach and may help to determine whether this technique is worth using in similar situations on other sites. I hope all the hard work pays off!

Fridays tend to be a day when we have a nicer than normal tea break. Some of the family came by to join in and we had a nice gathering in the cabin before getting back to work down by the river. We were spoilt for choice with home-made scones, which always go down well, and Deirdre also brought some extra goodies as well. They always did say that an army marches on its stomach and it is very important to keep morale up. We’ll certainly need it next week.

Rossnaree excavation

Friday tea-time


Day 14: No drama today, just another day’s work

No thunder or lightning today, just one or two light showers of rain. No sun either and the day was a bit cooler than previous but nonetheless was quite pleasant.

Rossnaree excavation

Chris reads some levels

Now with the weather report out of the way we can move on to the work done on site today. In Trench 4 (I always seem to start with this one, possibly because it is the nearest one to the site) Kieran drew a plan of the cutting showing the extent of the ditch, the slopes to the base on each side and the rest of the cutting. This view complements the section he drew yesterday – the section shows the side-view or elevation of all of the layers in the side of the trench while the plan view gives the bird’s-eye-view of the feature excavated. At the same time, I took a series of soil samples from the sides of the trench for magnetic susceptibility analysis. Samples had been taken previously at a higher level and readings have also been taken across the surface of the trench before the trench was desodded so we will end up with a very good record of how magnetic susceptibility varies with depth within the ditch. To remind readers, magnetic susceptibility measures the ability of the soil to become magnetised when a magnetic field is introduced and is a very good indicator of past burning or disposal of organic material like food waste or manure.

Rossnaree excavation Trench 4

Chris and Kieran level the site.

Both of these are of course closely related to settlement. The soil samples will have to be processed at a later stage after the excavation is over before the analysis takes place. They will be dried, sieved to remove stones and weighed to produce equal sized samples. In this way, we will be able to get accurate and directly comparable values for magnetic suceptibility. At the end of Kieran’s planning process, the final job to be carried out is to take levels of the area to give an impression of how undulating the planned surface is and to give a feeling for the relative depths of features. This is done on site with a simple dumpy level, which is being used in the photo by Chris who was visiting the site this morning. Chris was one of the geophysics team who first discovered and mapped the enclosure back in 2008 and he was anxious to see for himself how progress was going. In the photo, Kieran is holding the staff, which is like a giant ruler. He places this on each spot in the trench that he wants measured and Chris takes the reading through the level, which is like a small telescope that has been set up on the level. We know the height of the level in space (this has been established already) so we can calculate the heights of each point measured and recorded by Kieran on the plan.

Rossnaree excavation Trench 3 artefact

Intact flint blade from Trench 3

In Trench 1 the work of the past number of days went on and Darren and Matt removed more of the dark, rich organic layer overlying the cobblestones making up the core of the bank. Lots more animal bone was found, some of which seems to have been burned (this will hopefully be confirmed by our animal bone specialist who is visiting next week). Some nice pieces of flint were also found including various flake fragments, a scraper fragment and a complete blade.

Rossnaree excavation Trench 3

Cobbles in the bank in Trench 3

Beneath this layer the cobble stones were coming up very nicely and the site in this area at least was beginning to feel more than a little like an early medieval cashel. Because these date to between 500 and 1000AD, I wasn’t too happy with this idea! I still believe the site is Neolithic (4,000 to 2,500BC). I believe the staff have a book open on the date; one bet is that it is 850AD. Traitors! Seriously, no artefacts have been found that suggest that this site is anything other than prehistoric (and probably Neolithic) although, as I said before, some pottery would be very nice and would help remove any doubt. The cobbles in the wall do seem to have collapsed a bit over time; they are most intact at the bank end and less distinct moving eastwards away from the bank. There is also a lot of soil in between them which probably filtered down from above over the years too.

Rossnaree excavation Trench 1

Stony fill in Trench 1 ditch

In Trench 1 more progress was made removing one of the ditch fills. Gary and Niamh cleaned up and exposed the layer of stones within this layer and, although at first glance they seem to have a pattern to them and appear to be part of a structure, this is completely coincidental. The excavators are certain that this just happens to be the way the stones settled after rolling or sliding down the slope from above, finally settling at the lowest part of the ditch. We will clean them a bit more and record them in plan anyway, just to be sure.

Rossnaree excavation crew

The team admire their handiwork


Day 13: Thunder and a skull

The day started out well in line with the Met Éireann predictions. However, the forecast was for deteriorating conditions with frequent heavy showers in the afternoon. It was looking like we were going to lose some time. However, it only rained once at lunch time but it was a very heavy and prolonged shower. Once it finished, despite being surrounded by slaty grey thundery clouds, it stayed dry.

Rossnaree excavation Trench 4

Kieran plots the section in Trench 4

In Trench 4 Kieran got stuck into recording the section. The process is to set up a baseline making sure that it is level. In the photo this is just below the edge of the trench and there is also a long measuring tape attached to it to help with the drawing. This is used to measure down to points to be recorded, e.g. the tops of layers, stones, the edges of a ditch. Each point is meticulously measured and plotted on a scale drawing so that there is a permanent accurate record of the material that has been dug through on an archaeological excavation. It is like a giant version of join-the-dots.  Kieran was recording the various fills of the outer enclosure ditched as revealed in the side of Trench 4. Even with all of the modern technology that is available now, there is still nothing to beat the trained and experienced eye of an archaeologist, especially the person who has dug the particular trench. Some of the differences between layers are so slight and subtle that they are beyond the ability of machines to detect and must be drawn by hand. Even with all of the advances in digital photography it is still best to do this job the tried and tested way, even if it does seem slow.

Rossnaree excavation Trench 1

Progress in Trench 1

In Trench 1 Niamh and Gary continued to take down ditch fill material, sampling as they go. A layer of stones has appeared and the base of one of the layers that hasn’t shown previously do the plan is to expose the stones to see if they form any pattern or whether they join with any of the other stony layers exposed in the section. Although they are likely to be material that has gradually slipped down the slope from higher up coming to rest in the upper fills of the enclosure ditch, tomorrow should reveal full their extent and allow us to decide properly why the stones are likely to be there. In the photo it is possible to see the clear difference in colour between the face of the bank and the ditch cut, both of which are stony and more grey in colour, and the fill material which is much more brown.

Rossnaree excavation

Eimear and Deirdre on the Trench 1 sieve

Very good progress was made in Trench 1 today because of the extra personnel there. Deirdre and Eimear took over sieving duties for Matt and Darren so that the digging cound take place continuously. Good finds were still being found through sieveing including the usual animal bone and flint. The animal bone assemblage is increasing in size and although we are only recovering fragments in most cases, we hope that analysis of the bone will be able to tell us about the economy of the site, i.e., what they were raising and eating.

Rossnaree excavation Trench 3

Matt examines the cobbles in Trench 3

The picture of what is happening in Trench 1 is changing rapidly as a result. It now seems that the point where the ditch met the bank was defined by large cobbles which were mentioned already. These cobbles seem to have served as a revetment or low wall keeping the core of the bank in place and they also seem to mark the edge of a layer of cobbles within the wall. These will be further revealed over the next day or two and hopefully it will become clearer to us as to what they were for.

Rossnaree excavation Trench 3

Matt trowels around the skull

Towards the end of the day, however, another interesting find was made. A theme has been developing over the last few weeks that we’ve been finding cattle bones in significant places in the excavation today’s find was yet another example of this trend. Set on top of (or possibly within) the cobbles on the bank in Trench 1, what appears to be a cow’s skull began to be revealed. This may just be rubbish thrown out from higher up in the site but at the moment it appears to have been perhaps deliberately placed within the material in the bank of the inner enclosure. Is there a real theme developing in this site? Are cattle somehow important to what the site was used for? Hopefully we’ll have some answers before long.


Day 12: Here comes the sun

So much of what we do in Ireland revolves around the weather, especially for those who work outdoors. You tend to notice every little gust of wind and cloud that crosses the sky to a much greater extent than those who have to work inside each day. Day 12 was a good day weatherwise and there were no interruptions from above. We even had to break out the sunblock. A few more days like this between now and the end and we should be alright!

Rossnaree excavation Trench 4

Trench 4: ditch with muddy water

In Trench 4 Kieran, Deirdre and Eimear dug as far down as they could go. Because of the water level in the bottom of the ditch, they were unable to keep digging. The water was so muddy that it was impossible for them to know what they were digging and while it seems that the ditch does go deeper because of the slope of each of the sides, at the moment it is too wet and messy to dig. We also checked to see the relative level of the water in the trench compared to the level of water in the river. We did this using a dumpy level and believe it or not, the river level is actually about 30cm higher than the ditch water level. This is not what you would normally expect. Furthermore, we tried to bale out water from the bottom using buckets, and as we did so, fresh clear water flowed in from the direction of the river. It seems that the water level in the river rises more quickly than the local water-table. By the end of the day, we decided it was time to start drawing a section – the vertical side of the trench. This is an important part of the recording process and will help explain some of the processes

In Trench 1 Gary and Niamh continued to take out the upper ditch fills across the outer enclosure ditch. They succeeded in completely removing one of the layers, taking a bulk sample of the soil for future specialist analysis, and began to remove the next one, also sampling it and removing it. Good work was done and the level of the trench is steadily coming down. More and more ‘natural’ or undisturbed, non-archaeological soil is becoming visible.

Rossnaree excavation

Eimer and Deirdre leave Trench 4 for Trench 3

In Trench 3 Matt and Darren continued working on the ditch fills there especially the area overlying the bank at the eastern side of the trench. The geophysical survey carried out prior to the excavation suggested that this inner area to the east of the bank was lower resistance, perhaps more moist and organic. The more digging that Matt and Darren do in this area, the more the initial geophysics is proven right. The soils in this area do indeed appear to be different to the others over the ditch and may represent an area where rubbish was disposed of creating a midden or ‘compost heap’ layer of decayed organic material. Because this was so long ago, this material doesn’t look like compost but the soil is slightly darker and richer than those around it and definitely suggests that there is organic material in it. When we sample this soil and the specialists take a look, we will know for certain. Matt also did some work on the section face – the vertical side of the trench – to work out the exact sequence of layers and fills and their relationships to each other. They also uncovered a bit more of the layer of large cobbles in the edge of the ditch.

Rossnaree excavation Trench 3

The excavation surface in Trench 3 today

This may have been a deliberate design feature where the inner face of the ditch (outer face of the bank) was cladded in large stones. They may also represent a foundation layer upon which the bank was constructed. Work in this area has begun to speed up because Matt and Darren were joined by Eimear and Deirdre from Trench 4. As Kieran is drawing there, there is nothing for them to do so they were redeployed as the Trench 3 support team.

Rossnaree excavation

Another day is done...


Day 11: The ‘difficult’ third week

Well, it’s hard to believe we’re at this point already. The time is rushing steadily by at a worrying speed. However, today we are joined by some additional volunteers: Gary and Niamh, both of whom are postgrad students in UCD. Their arrival is very timely and is greatly welcomed.

Rossnaree excavation Trench 4

Kieran, Eimear and Deirdre in Trench 4

In Trench 4 Kieran, Eimear and Deirdre put in another amazing day bringing the ditch down. They are beginning to find the bottom of the feature which is comparable in depth to the other two ditches in Trenches 1 and 3, if not a bit bigger. Eimear is almost the full depth of the ditch as it stands at the moment, and there is still a bit to go. There is water at the bottom of this ditch – we did have quite a wet morning after a wet week-end and the water level in the river is noticeably high compared to last week – and we wonder whether this is the level of the water-table or even the level of the water in the river. Given that the material beneath the cultivation soil into which our ditch is cut is almost pure gravel, this is at least possible.

Rossnaree excavation Trench 4

The ditch deepens in Trench 4

There aren’t likely to be any major impermeable barriers between the location of Trench 4 and the river. I am promised that the edges of the ditch will be beautifully sculpted tomorrow and that the bottom will be reached. Hopefully the water levels will fall overnight to facilitate this!

In Trench 3 Matt and Darren continued to explore the fills of the ditch and the bank in that area. As reported on Friday this ditch is more substantial than was anticipated earlier in the dig and now looks as if it will be the same sort of dimensions as the outer enclosure ditch uncovered in Trench 1.

Rossnaree excavation Trench 3

Darren trowelling in Trench 3

We are looking at a ditch up to 4m across at the top with a depth of up to 1m. Work went well here during the day (despite everyone losing an hour or two in the morning because of the misty but persistent rain which prompted an early tea break). The edge had been already established on the west side of the ditch and attention was then focused on the east side of the trench to see if an equivalent edge could be established. During the late morning some very large cobbles were encountered in the cutting leading to suggestions of a possible revetment or wall-like feature on the face of the bank. Further investigation revealed that although these were substantial stones, they were not sitting in courses as we would expect with a wall but they did seem to be sitting on a berm or a shelf on the face of the ditch. Are these a deliberate feature or is this just where some of the stones from further up the bank finally settled. Maybe we’ll find out more when we dig a little more. Because of these stones obscuring a possible edge on the eastern site of the ditch, the lads decided to follow the known edge and peel off the fill from the west side instead. This paid off because early after lunch they found the base of the ditch.

Rossnaree excavation Trench 3

Matt records the find of the rib (lying beside trench to the right)

I know there s a myth about lightning striking twice but it looks as if it struck twice at Rossnaree! Last week we were very lucky to recover a cow’s mandible from the base of the ditch in Trench 1 which is (hopefully) ideal for radiocarbon dating. Well, out of the bottom of the ditch in Trench 2 what did they find but an almost complete cow’s rib. This was in almost exactly the same location in the ditch and the two deposits suggest that their placement was a deliberate action and a feature of the site. It is surely too much of a coincidence to be anything else. I wonder what we’ll find in the base of the ditch in Trench 4. This find is great, again for dating purposes.

Rossnaree excavation Trench 3

Trench 3 ditch section

If it proves possible to get a radiocarbon date from this bone sample, we will have a date for the use (close to initial construction) of the site. It is possible that the various enclosures around the site were constructed at different times so we would have comparative dates telling us how much time elapsed between the construction of the two ditches. Alternatively, the two may have been constructed at the same time which has another set of implications about the planning and possible functions of the site. Are these deliberate deposits or are they just representative of waste disposal practices? So much food for thought.

Rossnaree excavation Trench 1

Niamh and Gary take soil samples in Trench 1

Finally, in Trench 1, Gary and Niamh took the task of taking down the layers filling the ditch in the southern side of the trench. These are being bulk sampled for macrofossil remains. This means that large samples of the soil are being kept (between 5 and 10 litres) for processing at a later date in the hope of retrieving a variety of environmental indicators like seeds, charcoal and other plant material. These will be separated and retrieved from the samples through a technique known as flotation where the soil samples are added to water and the vegetable fraction floats to the surface and can be skimmed off and can be later analysed and identified by specialists giving important information on the environs of the site and how they looked and were managed at the time the site was in use. Not as exciting as finding cattle ribs perhaps. Unfortunately it will take some time before the results of this particular exercise are known.


Day 10: Half way! ‘A lot done, a lot more to do…’

Rossnaree Excavation Trench 4

Kieran and Deirdre in Trench 4

We are now at the end of our second week; day 10 out of a total of 20. Am I a glass-half-full or glass-half-empty person? I think that the rate of progress has slowed a bit in Week 2 relative to week 1 but this was inevitable. We had a larger crew in Week 1 and a lot of material was moved – desodding and topsoil. The nature of what we are dealing with now means the work now has to take a slower pace. We are trowelling a lot more rather than mattocking and shovelling. We also have to stop digging at intervals in order to record the features we uncover. However, there have been important successes. Nothing that has been found so far on site suggests that the enclosure is anything other than Neolithic in date. Although there has been no pottery yet (which is closely dateable because of their fast-changing shapes and decorative styles over time), there has been a lot of flint pointing to prehistoric and probably Neolithic or Early Bronze Age construction and occupation.

Rossnaree Excavation Trench 4

Trench 4 section showing enclosure ditch cut

Anyway, the news for today is that first of all, the weather turned out much better than we were expecting. After the near wash-out on Thursday we had been expecting blustery showers all day. The wind didn’t materialise and there was no rain at all. As a result we managed to get some more work done. The success of the day was that in Trench 4, Kieran and Deirdre were really getting to grips with the nature of the enclosure ditch. The edges had been clearly established and they began to take down the fill. Although the ditch was not bottomed we are definitely in the right place and the base is not far off. Digging finished up at a level characterised by a layer of field stones which must have spilled in from one side or the other. The fact that they are so deep down in the fill suggests that this event may have taken place relatively early in the life of the ditch. This layer may be comparable to the ‘spill/slump’ layers of stones identified in Trenches 1 and 3 and the stones may have come from a bank feature that once would have stood along the inner edge of the Trench 4 ditch. There is no sign of such a bank today in any of the data we have – aerial photographs, LiDAR, and the various geophysical outputs – but it is likely that there once was one in this area comprised of the spoil dug from the ditch. There are very few finds from this part of the site; although they are there the numbers are extremely small compared to Trench 1 and especially Trench 3 close to the core of the site. Perhaps there wasn’t much activity in this part of the site. Even today, this is an area subjected to regular flooding during winter and would have been the same in the past. It would not have been a wise location to construct houses or other structures. Perhaps the stony layer so far down in the section suggests that there was less concern in maintaining this part of the site compared to the sections of ditch in Trenches 1 and 3. The fill of the ditch looks promising for the preservation of macrofossil plant remains and perhaps pollen. Snail shells were also noted in the fill here and soil samples will be taken to examine the specific species present as snails (molluscs) are very sensitive indicators of the environmental conditions in an area in the past.

Rossnaree excavation Trench 3

Work in progress: the ditch section in Trench 3

Work also continued in Trench 3 where Matt and Darren continued to explore the fills of the ditch there. We had been speculating as to the probable depth of the ditch here. One set of geophysical data was suggesting that it was not as substantial as the outer enclosure ditch encountered in Trench 1 while another set of data was saying that it was comparable in size. I had thought that it may be less substantial as it was an inner enclosure but the digging here today suggests that it may be as big as the Trench 1 ditch. A considerable depth has already been reached and the signs are that it is still going down. More to be revealed as we continue early next week.

We also had a number of visitors to the site today: Gabriel, Steve, Aimée, Kim and Emmet from U.C.D. as well as Bryn who is visiting home from Australia and Michael who helped out on site in the first week of the dig. They reminded us once again of what a wonderful place we are working in. I think we may have begun to take our surroundings a bit for granted, and of course the weather wasn’t helping.

Regarding the question posed at the top of this post, I think I have to say that the glass is definitely half full. Maybe even more…


Day 7: ‘Now you’re sucking diesel’

Rossnaree excavation

Darren digs the top of the Trench 1 ditch

The weatherman had warned of rain spreading into Munster and south Leinster by midday spreading to all areas over the afternoon so we were apprehensive about when this weather would actually arrive. The day was not as bright and as sunny but was still dry. The big news for the day was that we were joined by reinforcements in the form of Deirdre, a veteran of many previous excavations including Graeme Warren’s dig at Belderrig and Geraldine and Matt Stout’s dig at Site M, Knowth. A valuable addition to our small team.

Work focused on two areas today: Deirdre and Eamonn under Kieran’s supervision began to work down through the topsoil/cultivation soil in Trench 4, the site of the geophysical survey work on Saturday. Ultimately, the excavation of this trench will be a test of the accuracy of the various techniques we used during that survey.
The other area of activity was in Trench 1, continuing the explorations started yesterday tracing the extent of the ditch of the outer enclosure. Work went very well and by lunchtime, Matt had found the bottom of the ditch and by the end of the day he had found the sides of it as well, at least on one side.

Rossnaree Excavation

Matt digs the base of the Trench 1 ditch

The ditch turned out to be around 90cm deep, pretty much the depth indicated in the ERT section carried out over this area some time before. This is a very good result for us excavating the site, but also for Kevin, who has hard evidence to show how well the equipment works.

As if that wasn’t enough, out of the very base of the ditch, at 4.40pm, almost when the day was done and it was time to pack up to go home, Matt made another discovery. At the very base of the ditch, he uncovered an intact cow’s mandible. You may wonder why you should be excited about this. Granted, it is not the most exciting find and you’re highly unlikely to find one of these in any museum display. The main value of this find is that it can be scientifically dated using radiocarbon dating and an independent scientific date for the site can be established. It was in the perfect location for establishing an accurate date; right at the bottom of the ditch. This means that the bone must have made its way into the ditch very soon after the ditch was dug, presumably while the site was in use. If the bone was further up in the fill of the ditch, it could have made its way into the ditch some time later and thus would not be a reliable indicator of the earliest use of the site.

Rossnaree excavation

Matt displays his cow's mandible (lower jaw).

Furthermore, it seems that the bone may have been deliberately placed at the base of the ditch because it was found in a small ‘slot’ feature right at the base. This would further connect the bone to the initial digging of the ditch and the earliest use of the site.

Rossnaree excavation

The mandible.

It seems inevitable that there will be some rain over the next couple of days. Hopefully not too much!


Day 6: The glorious twelfth…

And it was certainly a glorious day today on the banks of the Boyne. A welcome change from the persistent rain of Saturday and the torrential showers of Sunday. Very worrying for the coming week. It was a quiet day on site today because of the departure of three of the team at the end of last week. We are expecting some new blood tomorrow all going well and they will be very welcome.

Rossnaree Excavation

Glorious...

Today, the main focus was in Trench 1 on the slope of the gravel terrace on the northern side of the site. Having exposed and recorded the surface of archaeological layers by the end of last week, we now took a closer look at the separate components within this surface (see Day 4 blog). We had to determine which layer we should excavate next. There are two banks in Trench 1 and on either side of these banks there appears to be a layer of larger stones in a position that suggests that they may have slipped downwards off the bank itself. This material is likely to be lying on top of the junction between the ditch (fosse) and bank. The ditch, although visible on the surface as a dip in the ground surface, is not open to its full depth because in the years since it was dug various processes have been at work filling it back in again. Rainwater washes clay and soil downslope from the banks which settles in the low ground of the ditch. Sometimes stones roll down the slope into the ditch as well. Animals walking over and back over the banks wear them down and encourage movement of material into the ditches. Very often when sites were lived in, ditches were used as convenient landfill sites so a lot of food and other waste made its way into them. Thus the soils of ditches are often looser than the soils around them, they often are less stony and often have organic domestic waste in them, including charcoal, which makes them different to the soils of other features around them. While we have identified an area where the material is very likely to be ditch fill, we are currently trying to find the extent of this material, i.e., where are the edges. This is tricky because of the large amount of smaller stones in the soils and also because the soils are so similar in colour. However, we are confident that we will resolve this before long. There are still finds including flint and animal bone coming out of the soil we are digging so we know that it is fill; these materials could not have found their way into undisturbed natural soil.

Lots more to be done tomorrow. Hope the rain holds off.


Week-End 1: No rest for the wicked!

Electrical resistance tomography Rossnaree excavation

ERT section over Trench 4, Rossnaree

No, I’m not telling you how much washing I had to do after the first week or how long I slept for. In fact, although the team had both days off over the week-end, Kevin and Mark of Landscape & Geophysical Survices came down to the site with me to do some geophysical surveying on Saturday (in spite of the very persistent, and sometimes heavy, rain). There were a number of questions to be followed up on and pieces of work to be done. Firstly, we needed to carry out an electrical resistance tomography (ERT) survey over the line of Trench 4 before it is excavated. This had been done previously along the bank where Trenches 1 and 3 are located. This is a little used but very useful technique because, unlike other more conventional geophysical survey methods like magnetic gradiometry or earth resistance which produce map-like plots, and ERT survey produces a section along a line, so it takes a vertical slice downwards across the line chosen. If you are planning to excavate a series of substantial cut features like ditches, this is an ideal technique as it lets you know exactly where the feature is located and it also gives an indication of its depth. Very useful information if you are trying to budget out how long a job might take. An electrical signal is sent down into the soil which is reflected back upwards. The signal is distorted depending on the depth and the nature of the obstacles encountered.

For those of you interested in the technical details of the technique, ERT uses a series of electrodes to pass an electric current into the ground and measure a resulting voltage. Using the values of current and voltage a resistance can be calculated using Ohm’s Law. The depth of penetration of the current is a function of the spacing of the electrodes, the wider the spacing the deeper the current flow. By selectively increasing the electrode separation the resistance of the sediments existing from the ground surface to greater depths can be measured. In order to compensate for the increasing electrode separation each resistance value is multiplied by a factor based on the electrode spacing and it becomes a resistivity. The resistivities are then plotted on a pseudosection which represents the distribution of resistivity with depth. In order to relate the overall resistivity distribution to the individual resistivities of host sediments and possible buried archaeological features such as ditches and walls the resistivity values in pseudosection are subjected to a computer modeling process. This process results in a more realistic model or section of the surface which then can be interpreted in terms of the possible archaeology intersected by the section.

Rossnaree excavation

The ERT survey results.

In the case of Trench 4 we are trying to locate the outer ditch seen in the magnetic gradiometry data. The ditch can be seen as a lower resistivity feature about 9m along the section. The lower resistivity represents the fill of the ditch. Underneath the ditch is even lower resistivity and we are wondering if this is due to clays laid down by the River Boyne and/or water saturated sediments. The excavation may reveal the answer to this question.

magnetic gradiometry survey Rossnaree Excavation

Mark carrying out the magnetic gradiometry survey

The next job we had to do was to trace the full length of the outer enclosure. Earlier survey work had established that this feature continued from the tillage field into the pasture field to the east (where Trench 4 is located). However, we had yet to fully map its entire length. Mark did this using a magnetic gradiometer, the same kind of instrument that had been used previously. This detects minute distortions in the earth’s magnetic field caused by the properties of the soils close to ground surface. Archaeological features like fireplaces and the fills of pits and ditches often contain soils and materials that will affect the earth’s magnetic field and these very sensitive instruments are capable of detecting these changes. This survey was successful and, although there had been a lot of disturbance of archaeological features by later cultivation, the line of the ditch was detected traveling eastwards to meet the riverbank where we guessed it would.

ground penetrating radar survey Rossnaree Excavation

Kevin carries out the GPR survey

We also took the opportunity to carry out a survey with another technique: ground penetrating radar (GPR). This technique works like an ERT survey. A signal (in this case radar, a type of radio wave) is sent downwards into the ground and is reflected back to the surface by different materials. The nature of the reflected signal received on the surface by the unit can tell about what it is (hard, soft, void) and its depth. Thus a vertical slice, like with ERT, is obtained. However, when a series of parallel lines is surveyed, and the data are downloaded and processed with the appropriate software, we end up with a 3-D model of the sub-surface archaeology of the survey area.

We look forward to seeing the results of this one and depending on the success of the survey and the quality of the survey, I’ll give you a look too. Watch this space!


Day 5: The first week’s done!

Soil sampling for lab magnetic susceptibility analysis

Mark taking soil samples for magnetic susceptibility analysis

What an eventful week. An enormous amount has been achieved in a short space of time thanks to the enthusiasm of a great team. Four trenches have been opened up and fully desodded. Two of these have been cleaned down to archaeology and the first clear intact contexts/features have been identified. These have been recorded over the last couple of days by drawing, photography and in writing and another series of soil samples has been taken. So if it seems that there is no digging going on in some trenches that’s true but this is essential in order to give time to properly and meticulously record everything. Detailed recording is essential at this stage and is important because once a layer or feature is dug out, it is gone forever; it is not possible to put it back and take another look.

Most of the crew were transferred across to Trench 5 to give time and space for recording in Trenches 1 and 3. This is c. 1.5m out from a whitethorn hedge and contains the greywacke slab I spoke about before. The hedge is great  because it is quite old and well-developed and it means that the crew was working under a natural umbrella. There were only a few showers on Friday but the foliage is so dense that it remained perfectly dry underneath.

Rossnaree greywacke excavated

The greywacke slab on excavation

The suspicion about the slab is that it is not resting in its original position. It is lying embedded in the ground lengthways, parallel to the field boundary/hedge and protruding at an angle from the ground along its width. The upper surface has a series of grooves cut into it (see the third Day 3 photo). This is not ogham nor is it megalithic art (unfortunately) but is damage from metal ploughs being repeatedly dragged across that point of the slab, year after year. It looks like the slab was originally buried in a tillage field just at the base of the ploughsoil and one year, instead of scraping over the top edge of the slab, the plough caught it and pulled it up. The ploughman then pulled the stone to the side of the field out of the way and it made its way to its current position. Because the stone is at the top of a slope in its current position, it looks like it may have been thrown through/over the hedge from the field next door, i.e., the field where the centre of the Rossnaree Enclosure is located. Perhaps there was a standing stone in or close to the centre of the site. The field where the stone is lying was itself cultivated in the past. Indeed on the lidar imagery (see the background of the montage image on the home page) the field has a clear ‘corrugated’ surface showing the line of cultivation ridges. Because of this, it looked like the stone was ‘floating in at at the top of cultivation soil rather than being bedded into an archaeological feature below the surface.

Rossnaree Andrew lignite

Andrew proudly displays his find

However, as this was only a theory, the safest approach was to excavate the disturbed cultivation soil from around the stone to expose the base and check what it was lying in. This is what we did and by Friday evening, although we hadn’t reached the base of the cultivation soil, we had exposed the bottom edge of the stone and were able to determine that it was lying completely within disturbed cultivation soil and was not in its original position. Thus it is safe to lift the stone and arrangements are being made to do this using appropriate equipment. It is definitely too big to lift and transport by hand. A nice selection of finds came from the area including several pieces of flint, some chert, a lot of animal bone, lots of bits of barbed wire and, best of all, a portion of a lignite bracelet.

Rossnaree Trench 5 lignite bracelet fragment

The portion of lignite bracelet from Trench 5

This was definitely find of the week although there was some speculation that it was ‘…just a bit off a tractor..!’ Maybe they’re right! If it is a lignite bracelet, it could be either Bronze Age in date or Early Medieval. Either way, it is likely to have been a prized personal possession of an individual and it is amazaing to think that a portion this big survived so well for so long in a very dynamic context, i.e., soil that was ploughed or cultivated every year for possibly centuries.

Rossnaree Trench 5 sieve

Valerie and Andrew sieving for finds

As usual, all spoil excavated from the trench was passed through a 5mm sieve. It was very useful using the sieve as this is how most of the finds were identified. A different sieve arrangement was used to that used for Trenches 1 and 3. This is designed to be suspended from some sort of frame but was used without a frame here. Thanks to Emmet for both designing and manufacturing the sieve to such a high standard. The handles are a particularly nice feature!

Rossnaree Trench 5 Reinforcements

The relief crew: Clíodhna and Cillian 'will work for biscuits'!

The work on Trench 5 progressed very well and we were joined for a short while for a new crew of volunteers who negotiated payment for their efforts in the form of biscuits! Come to think of it, that’s what the rest of the volunteer crew are working for too, thanks for pointing that one out to me Eamonn. I suppose it’s better than working for peanuts!

Being the end of a week, we unfortunately had to say goodbye to some of the crew. Ailbhe had left on Thursday evening for Oxigen (we hope it doesn’t rain too much!) and then Valerie and Andrew finished on Friday evening although there is a strong possibility that they may be able to return for a few days later in the dig. The bug has really bitten there. A big thanks to them for taking part and helping to make the week so stress-free and enjoyable – I think we all learned a lot as the days went by.


Day 2: Getting down to business

Everyone is beginning to get settled in and a routine is becoming established. After yesterday’s successful campaign of desodding, today’s job was to clean down the cuttings and remove the remains of any of the sod layer left and remove the topsoil immediately below the sod. People got to use their trowels for the first time and the operation began to take on the feel of a real archaeological dig. Clearing started in Trench 3 and the team split into smaller groups for the different tasks.

Soil sampling for magnetic susceptibility analysis.

Soil sampling for magnetic susceptibility analysis.

Using a plastic trowel rather than a metal one to avoid contamination of the samples, Mark took soil samples on a 1m x 1m grid from immediately below the sod surface before cleaning down commenced . These will be processed later and the magnetic susceptibility of each sample will be determined at a later stage. A similar process was carried out on the surface before desodding took place using a field measurement instrument and additional samples will be taken as the trench is dug further. So as well as mapping the horizontal variation in magnetic susceptibility, we will also be able to look at the vertical variation and we hope that this information will add to the overall picture of how the site was used. Before I go on, in case you are wondering, magnetic susceptibility literally measures the soil’s ability to become magnetised.  What this idicates is where an area has been burned or where there has been a build-up of organic midden-like material which has rotted down (a bit like compost). Both of these processes cause chemical processes in the soil which can be detected and measured. Both of these characteristics are associated with human activity including settlement. More about magnetic susceptibility in the days to come.

Working at the sieve

Darren, Andrew and Valerie using the sieve

All of the material being excavated from the various trenches across the site are being sieved in order to maximise the number of finds recovered. A number of pieces of flint were recovered as well as a number of pieces of animal bone. The flint suggests prehistoric activity (possibly Neolithic). Is the animal bone the same date? Hopefully specialist analysis after the end of the dig will help to answer this question. If it is prehistoric or Neolithic, these bones could represent the remains of some of the dinners consumed by the occupants of the Rossnaree Enclosure.

A flint flake

One of the first finds: a flint flake


A bit of essential kit for the dig.

Rocker sieve

Rocker sieve to be used on the Rossnaree Excavation

Spent the morning assembling a sieve for use on the excavation which starts on Monday. It is a sieve with a 5mm mesh, essential for recovering the smaller pieces of flint from the ploughsoil and other contexts.

Rocker sieve detail

Rocker sieve construction detail showing 'rocker'

The design is ingenious and is based on a ‘rocker’ mechanism. The sieve mesh is mounted in a frame where the long sides have gently curving lower edges (a bit like a sleigh). This unit sits into a table-like frame on legs. The sieve can then be easily rocked from one or both ends, taking some of the effort out of the process. I look forward to testing it out, it should help to boost our finds tally.

Rocker sieve demonstration

Rocker sieve demonstration.

I think a similar design was used on the Bective Excavations Project last year – so they have no unfair advantage! Thanks to Liam for developing the sieve from ‘concept’ stage to a working reality!

We will also be using another sieve (we will be opening more than one trench) which will be based on a more conventional ‘suspended’ design. Big thanks to Emmet for designing, constructing and delivering that one. It will be interesting to compare performance of the two.


The low-tech ‘art’ of fieldwalking (surface-collection survey)

Walker in front of Newgrange

Volunteer walker on the Brú na Bóinne Fieldwalking Project in near Newgrange passage tomb.

The structural elements of prehistoric houses and shelters were chiefly constructed of organic materials, very little of which survive for any length of time under normal conditions.  However, we are fortunate that stone tools were used from earliest times through to the Bronze Age at least.  These tools are usually of flint and a number of other rock types were also used.

How artefacts enter the ploughzone.

How artefacts enter the ploughzone (after Haselgrove 1985).

In a ploughzone artefact scatter, finds that might normally be excavated from features on archaeological excavation sites have literally been ‘ploughed in’ to the ploughsoil with each tillage event.  The surfaces and features with which they would have been associated are now largely destroyed and only the deepest elements of trenches, pits and post-holes survive below the ploughzone.  The durable finds from the disturbed portion remain suspended within the ploughsoil and a proportion of these and later material are turned to the surface when fields are ploughed.

So, paradoxically, one of the processes that has contributed to the destruction of these site types actually allows us to ‘see’ beneath the soil without excavating.  In effect, the plough does the excavating for us.  The stone tools will, of course, be disturbed from their original contexts but generally speaking, scatters of material within the ploughzone will largely retain their spatial integrity and will be recogniseable if a suitable systematic method of recovery is used.

Weathered surface of a typical field during survey. Can you spot the flint?

Weathered surface of a typical field during survey. Can you spot the flint?

Research has demonstrated quite clearly that dense lithics scatters do not necessarily equate with settlement locations.  In many cases, large scale working of materials took place at a remove from the settlement purely for safety reasons; freshly struck flint flakes and waste is as sharp as glass; not a material to have lying around the house in large quantities!  There is a sequence which lithic raw material goes through from its initial quarrying and collection through to the finishing, use, resharpening, repair and eventual discard of tools.  House sites are generally characterised by material that falls into the later stages of this sequence and there are generally larger proportions of tools, utilised flakes and blades, trimming (retouch) flakes (which often require sieving to recover on excavations) and prepared platform cores than would otherwise be expected.

Close-up of some flint artefacts on a field surface.

Close-up of some flint artefacts on a field surface.

The most common method is to walk available (i.e., ploughed/tilled) fields using a grid system with regularly spaced transects crossing over the field, resulting in the sampling of the surface of the field.  The spacing of the transects is determined by the objectives of the survey.  If it is a priority to locate small ephemeral sites (like Mesolithic work areas) or establish the internal structure of larger scatters, then a relatively narrow spacing will be required.  If, on the other hand, a rapid assessment of presence or absence of artefacts relating to a series of different periods along with a rough indication of their locations is required, perhaps as a preliminary phase in a multi-stage landscape project, then a wider transect spacing will be adequate.  Each transect is subdivided into regular stints of a set length so each find will come from a recordable location, which facilitates the plotting of finds on distribution maps.  For the purposes of the current research, walkers were spaced 10m apart and stint length was set at 25m.  Each walker can effectively cover a corridor of c. 2m wide, i.e. 1m to either side of their path, resulting in 20% coverage of the surface of each field.

The procedure adopted here for laying out the grid was to first choose the longest, straightest field boundary to act as a baseline and then, using a sighting compass, to set out the transects and stints at right angles to this.  Transects and stints are marked with high visibility flags.  Each transect was assigned a letter in sequence and within each one, each stint was assigned a number.  Thus each stint will have a unique reference and finds are bagged according to what stint they come from.  The transect letter and stint number are the equivalent of a context number on a conventional excavation.

Grid used in each field in the Brú na Bóinne Fieldwalking Project.

Grid used in each field in the Brú na Bóinne Fieldwalking Project.

The results of the field survey, once plotted, can be easily replicated or tested under differing conditions.  Careful use of the same field grid from field to field is, of course, essential for results to be comparable.  Dull even light is the best for fieldwalking as there are no dark shadows created on the field surface.  Dry weather is, of course the preferred option for surveying; not only is it more comfortable but when the field surface is wet, colours tend to change to a uniform dark brown.  In well weathered fields, however, damp rather than wet conditions can serve to highlight the distinct colours and smooth surfaces of flint.  The number of walkers surveying on the day is also recorded along with the transects that they walked.  This is essential as different individuals tend to see different things on the surface depending on their levels of experience.  A subjective measure of each person’s experience can be made in order to weight areas that appear to be of lighter relative finds densities if it is felt that finds were being missed.

It is also important that fields be left for as long as possible before walking in order to maximise the effects of weathering.  Frost helps to break up larger clods while rain and wind help to clean stones on the surface.  Directly after the ploughing of a field very few artefacts will be visible.  As with much other archaeological work, patience is rewarded and six to eight weeks of weathering will result in dramatic differences in surface artefact visibility.  In the present survey, fields were usually walked some time after the crop has been sown, as a flat field surface is much easier to walk across than one that has only been ploughed.  However, there is constantly a trade-off between the quality of the surface and the length of the crop.  If a crop is left for too long it will damaged by walking on it, but generally speaking by this stage the crop is so high that it will begin to interfere with visibility anyway.

The finds are washed, catalogued and plotted on field maps.  Identification of scatters can take place once this has been done.  The assumption underlying this work is that the presence of a lithic scatter on the surface of a field is indicative of prehistoric settlement or work-related activity, not necessarily on that exact spot, but very close by.  The presence of diagnostic artefacts can give broad indications of the dating of particular scatters while an analysis of the composition of ploughzone assemblages can identify the behaviours that were involved in their initial production.  As has been mentioned already, lithic artefacts can belong to one of a series of stages in a sequence from initial collection through to eventual discard.  Based on these observations, it has been established that a range of different activities can be recognised.  Certain locations within the landscape may have been favoured above others for certain tasks.

Although this technique is not necessarily as exciting or attractive as some more high-tech approaches like aerial photography, geophysics or excavation, it remains an excellent way to analyse the uses of a prehistoric landscape on a large scale basis and in an extremely cost-effective way. Results of such a survey can then be used to target more costly high resolution techniques on areas that have potential in the form of artefact scatters. This approach is extremely successful and has led to the discovery of the Rossnaree Enclosure.