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

Archive for July 7, 2010

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.

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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