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

Posts tagged “flint

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

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Day 9: Soft day, thank God

Rossnaree excavation umbrella

Should we stay or should we go now..? Matt and Kieran are glad of Deirdre's amazing umbrella

We Irish have a ludicrous saying suggesting that we actually like the auld bit o’ rain now and then. Today might have qualified for the ‘soft day’ categorisation but there’s no way any of us on site were particularly pleased with it today. There were numerous heavy showers but the weather couldn’t make up its mind as to whether it was coming or going. The result was a lot of wettings and some very stop-start work. Anyway, the one good thing about the weather today was that some of our crew were not able to make it to site today because of other commitments. So not everybody had to be subjected to a soaking!

Rossnaree excavation Trench 4

Trench 4 in the rain

The work that we did manage to get done was limited but it nonetheless pushes us a little further towards our ultimate goal. In Trench 4, Kieran, Eamonn and Deirdre continued to peel the cultivation sol off the top of the fill of the enclosure ditch. Very few finds were coming out of the material being removed but Deirdre’s sharp eyes picked out a fragment of a rock crystal flake (sorry no photo). This is very small-less than half the size of your little fingernail-but is distinctive and unusual. Although more difficult to work into tools than flint (and harder for us archaeologists to recognise) it is clear that materials other than flint were often used by people in the Neolithic. In some cases it seems simply that where there was a shortage of good quality flint, people used other materials like chert and quartz as ‘second best’ alternatives. However, it is also possible that the materials chosen for toolmaking reflected the intended functions of the tools or reflected the identities of the people making the tools. We all have the good crockery at home for when visitors call. Similarly, craftspeople today often use unusual or distinctive materials as a sort of trademark. Perhaps this was going on in the Neolithic as well. The flake fragment we found is distinctive because it is a type of quartz which is almost transparent, like glass. This quality would not have been lost on the Neolithic people.

In Trench 1 we continued to take out the fill of the gully and we also drew the north-facing section exposed when we excavated the enclosure ditch. We also plotted the locations of the magnetic susceptibility soil samples we took yesterday. We managed to complete these various jobs by lunchtime between showers and then we transferred over to Trench 3 where there is also a bank and ditch feature. The plan was to start to take down the material filling the ditch in the same was as in Trench 1. We unfortunately didn’t get much done because of the rain but we did notice a larger number of bone fragments compared to Trench 1, reflecting the position of Trench 1 closer to the ‘core’ of the site.

Rossnaree excavation

Soft day...!

Can’t decide whether the weather forecast was accurate; I think it was today. A blustery day is forecast tomorrow with scattered passing showers. I think we may be able to cope with that.


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.


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 3: Establishing a routine

The weather is holding up well despite the predictions. Today we finished clearing off in Trench 3, which is close to the core of the site, and moved over to Trench 1, which has been set out over the outermost bank and ditch, to continue the process of cleaning down. In the same way as before, all of the topsoil from beneath the sod is sieved in order to make sure we get as many of the finds as possible. It seems that there was less activity at this end of the site as there are generally fewer flint pieces and much less animal bone than in Trench 3. Clearly, different activities were being carried out in different parts of the site. Possible domestic/residential activities were taking place close to the high ground in the centre of the site within the inner enclosures while there seems to have been different kinds of activity elsewhere. Hopefully as we dig further we will get a better sense of what some of these activities were.

planning

Kieran demonstrates the art of archaeological planning to Ailbhe

The surface of Trench 3 was photographed, depths were taken and Kieran and Ailbhe got a start on planning the surface with a 1m square planning frame. This is a tricky process in this trench because of the steepness of the slope: it is not possible to lay the planning frame directly onto the ground surface and the corners have to be propped up to keep it level. The draughtsperson has to take care to look through the frame from directly above in order to accurately record the ground surface. It is a slow laborious process but it is still far better than a photograph because of the amount of detail it captures. Once Trench 1 has been fully cleaned down, it will also be photographed and planned in the same way.

Magnetic Susceptibility survey

Mark takes a magnetic susceptibility reading using a field loop.

We set out another trench, Trench 2, using a total station and we will move into it depending progress in the others. Once this was done, a magnetic susceptibility survey was carried out across the surface using a field instrument (see the Day 2 post for an explanation) and soil samples will be taken as the trench is dug. Using the field loop, care has to be taken to ensure that the loop is as fully in contact with the ground surface as possibly, otherwise an incorrect reading will result.

Greywacke slab

The slab of greywacke at the Rossnaree Enclosure.

Other work carriedout on site today included setting out the final cutting, Trench 5. This is positioned around a greywacke slab lying half buried in the surface of the pasture field close to the hedge and the plan is to excavate it and lift it. The significance of this stone is this is the stone type that was used for the structural stones in the passage tombs built on the north side of the river. Recent geological work on the structural stones of Newgrange and Knowth has demonstrated that the greywacke slabs used are likely to have been transported to Brú na Bóinne from the coast at Clogher Head, Co. Louth, a distance of c. 20km. This stone is very significant because it is on the south side of the river and it suggests that there may have been a link between those who occupied and used the Rossnaree Enclosure and the builders of the passage tombs. Were both in existence at the same time? There is also a possibility that there may be art carved on the stone, although none is visible at the moment. Although it is possible that this was part of a passage tomb, there are no other indications that one existed at Rossnaree. It may originally have been a standing stone like similar examples in the land below Newgrange and also at the mouth of the Boyne at Baltray.


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.