Excavation, Education and Experience: Archaeology at Ferrycarrig

This year we formalised a really exciting project that has long been in the making, a collaborative approach to research and education with biggest heritage park in Ireland, the Irish National Heritage Park. This project will roll into one our passion for research excellence, discovery, education and training, heritage interpretation and access.

The Irish National Heritage Park (INHP), situated on the Slaney river estuary, County Wexford, is an open-air museum which recreates the key stages in Ireland’s past. 

The park contains 35 acres (14 hectares) of outdoor museum situated within natural forestry and wet woodlands, with exhibits and activities representing 9000 years of Irish History. The exhibits feature interpretations and replicas of the site types and monuments that define Irish prehistory and history. Live action experimental archaeology and living history provides visitors and students with unprecedented access to the experience and theory that informs archaeological practice.

Excavation

In the earliest stages of the Anglo-Norman invasion of Ireland (C12 AD/CE), the advancing Norman troops built a large fortification on the prominent headland at Ferrycarrig, overlooking this strategic access point on the Slaney Estuary. The impressive structure would have comprised a wooden castle set on top of a large man-made mound with a bank and external ditch, sited on a natural promontory overlooking the River Slaney and Wexford town.  Nowadays, the large mound, bank and ditch are all that remain above the ground of this hugely important fortification, but archaeological excavations undertake in the 1980’s showed that substantial evidence from this troubled time is preserved below the ground. In the 19th century a war memorial, the design referencing the early Irish church round tower form, was constructed on top of this castle site, to commemorate those local soldiers who died in the Crimean War. The Irish Archaeology Field School will focus research investigations, and university anthropology and archaeology programmes on this site.

Education

The wider project, through provision of different ‘experiences’: the project will bring our cultural heritage to life by facilitating visitors engaging in the process of archaeological excavation, thereby witnessing discovery in action.  From the cornerstone of the excavation, a range of educational and practical experiences will be developed in the ‘Anglo-Norman’ section of the park that cater for the needs and interests of all ages, from young children, to the young at heart.  The location of the excavation site in the IHNP park facilitates access for the ‘non-student’, allowing the visitor to immerse themselves in the archaeology, with unprecedented access to the research excavations and experiential learning.

Experience

The IHNP is part of the ExARC network, the ICOM Affiliated Organisation representing open air museums, ancient technologies research, and the scientific research value of testing archaeological hypotheses through experimental archaeology. The park is host to one of the longest running experimental archaeology sites in the world, a prehistoric site type known as a fulacht fiadh, or burnt mound, currently interpreted as a cooking pit. The park has been experimenting with cooking techniques and feeding student and visitors for 30 years.

This wealth of knowledge and expertise informs a rich and accessible programme of experience for students and visitors alike, with programmes varying from demonstrations to immersive long-stay and overnight experiences.

The Age of Discovery

Collectively, in collaboration with IHNP park technologists, and with archaeologists and anthropologists from academic and technical disciplines, we aim to provide a new unique student experience, and give visitors to the park a unique insight into the process of archaeology (from buried find to museum display) in an engaging, up-close manner, through archaeological training, archaeological tours, open air museums, volunteer experiences and interpretive displays.

Exciting times!

 

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Of pots and layers: what stratigraphy and pottery can tell us

At the Black Friary, our pottery story tells us that the site was in use from the medieval period through to the early post- medieval period, and into the eighteenth century.Here, Black Friary Director and PI, Finola O’Carroll tells us how:

What is stratigraphy, and why is it important?

One of the most fundamental things that I try to teach students is to figure out how a site formed, and how can we make sense of the mounds of stone and earth that we’re confronted with and then tell its story? It’s a truism that archaeological sites are made up of deposits, laid down over time, which can then be excavated from the newest to the oldest. Theoretically, these can then be used to reconstruct the site and interpret it – how it looked and what functions it served. While these ideas were borrowed from geological laws relating to the formation of sedimentary deposits, this was not enough to explain and interpret the complexities of the average archaeological site. In 1973 Edward C. Harris developed a system now called the Harris Matrix (Harris 1975), which is a really useful tool used to depict the succession through time of archaeological contexts. Using this the sequence of depositions and surfaces on an archaeological site, otherwise called a ‘stratigraphic sequence’, can be drawn and makes understanding, analysing and interpreting the site easier and quicker. He developed this as part of his work on the really complex urban excavations at Winchester, England.

Harris believed that ‘the stratigraphic sequences of archaeological sites are made by the analysis of the interfaces between strata, not from a study of the soil composition of the strata. Without a stratigraphic sequence, the cultural remains of the strata cannot be contrasted except in a general ‘typological context’ (Harris 1979, 112).

Traditionally, excavators who worked in the first part of the 20th century such as Sir Mortimer Wheeler or Dame Kathleen Kenyon used a grid system to excavate which involved leaving baulks at regular intervals. A site would be divided up like a chess board, typically into 4m x 4m and 5m x 5m squares with baulks 0.5. wide between. The vertical faces on each side would be the reference point to analyse the stratigraphy. However, archaeological sites frequently contain many small deposits and features such as pits, which will not be represented in the vertical section faces at each baulk. This was the problem Harris was working on, and what his system was designed to cope with. Using his system each layer or feature is recognized, individually excavated and recorded descriptively and spatially before moving on to the next feature. In this way a matrix, or stratigraphic sequence can be built up, even though the deposits may not necessarily overlie each other directly. This practice was codified into the Single Context System as developed by the Museum of London Archaeological Service (MOLAS), which was designed to rapidly capture information onsite while digging, allowing for detailed analysis and interpretation post-excavations (see Spence 1993).

How do we use this method at the Black Friary?

At the Black Friary we use a slightly modified version of this system; understanding how to recognise features, and how to record a simple matrix which details the relationship of the feature to its immediate neighbours (on top of, beneath, beside or equal to) are fundamental lessons that students learn while digging. Integrating this information into the analysis of the artefacts and environmental material from each feature allows us to understand the events which trace an arc in time from the building, use-life, changes through enlargement or contraction of the friary, change of use post-reformation and dissolution, up to and beyond the time it was reduced to rubble by quarrying.

For those of you who’ve been following our progress, or have dug with us, you’ll understand the importance we attach to figuring out the stratigraphy and then analysing the artefacts found in each layer. We know, for example, that the rubble layers, almost always the upper layers over much of the footprint of the friary buildings, formed because of the quarrying of the site in the middle of the eighteenth century, (O’Carroll 2014). So, it follows that anything beneath those layers is earlier. We also know that the friary was built in the 13th century, so the earliest features should belong to that period. But figuring out what happens in between can sometimes be a little trickier.

How do we apply it?

View of east baulk of Cutting 7: cut F763 is visible to right, stone dump F765 is on the left, midden layers in the centre with F703 on top

Last summer (2016 season), excavations in Cutting 7 were extended to explore the north side of the north range; the deposits found suggested that a midden or rubbish pile had formed behind the north range in a series of very clear layers.  As a lot of animal bone was included it suggested that waste from kitchens formed the bulk of the pile. At the north end of the midden, where the wall should be, is a robber trench formed by the quarrymen digging down through the layers to extract the stone from the wall. That then filled up with loose soil in the area, in the place where the wall once was.

We recorded all these layers as they were excavated, by giving them unique numbers and by photographing, drawing and taking levels and co-ordinates under the supervision of Ian Kinch. All our feature, find and sample numbers incorporate the number of the cutting in which they were excavated. An interface is clearly shown here by the robber cut dug through the later deposits when the wall was taken down. This cut is visible as a clear disjunction between two sets of deposits to the right of the section face . In this stratigraphic sequence the deposits contained within the cut will be later than those in the midden, even where the midden layers are higher.

The features in the middle of the cutting can also be integrated with those in the section. The remains of two walls running N/S  have been cut by the robber trench, so we know they pre-date that event. But what is their relationship to the midden layers? The lowest exposed layer occurs on both sides of the narrower (eastern) wall. Other layers overlie this, some on to one side or the other, and some overlie the wall itself.

View looking north of walls F752 (left), F756 (right)

By using the Harris matrix, we can understand the sequence in which layers were deposited, cuts were made, and walls were built, even when they don’t directly overlie each other but occupy different areas within the cutting. When we have completed the excavations, we should know the exact relationship of the walls to these deposits.

What happens when we match the artefacts to the stratigraphic sequence?

We know that the sequence in the section face through the midden isn’t the whole story, but by looking at the pottery from layers in the section, we can see if the stratigraphic sequence is matched by a pottery sequence. Just by separating the pottery into medieval and post-medieval types from features F758, F755, F750 and F703, taken in order from the lowest to the highest will give us an idea of the pottery relates to the stratigraphy.

  • Feature 758 (F758 is the lowest midden layer. F758 is directly below F755, which in turn is directly below F750. The robber cut F763 and the fill of the trench formed by the cut, which is F753, cut these three features. All are capped by F703, which we can date to the destruction of the site in the 1750s.
  • F758, the lowest layer, contained a lot of pottery, 101 sherds in total. It was predominantly medieval in date, with 96 sherds of medieval pottery to only 5 sherds of post-medieval pottery.
  • The next layer, F755 contained a large percentage of medieval pottery, 28 sherds versus 3 sherds of post-medieval pottery were recovered.
  • F750 is being interpreted the upper layer of the midden deposit. Unlike the first two features, F750 has slightly more post-medieval pottery than medieval pottery, 16 sherds of medieval pottery were found as against 21 sherds of post-medieval pot. This is interesting as it shows the progression from medieval use to post- medieval use.
  • F703 is a destruction layer and made up of rubble collapse of the north range of the friary from the time of the destruction of the site in the 1750s. Here, medieval pottery again is dominant, with 37 sherds to 20 sherds of post-medieval pottery.

If we were to date the layers just on the cultural material contained within them, we would have to argue that all the layers are post-medieval or later in date, as all contain post-medieval pottery:

Table 1

By understanding the stratigraphic relationships, we know that F703 is much later than F758. We can explain the high proportion of medieval pottery in the latest layer by the fact that we know that earlier layers were dug through to access the wall to dismantle it. This would have meant that earlier deposits were mixed with the later material. The presence of the few post-medieval sherds in the lowest excavated layer may be a result of later contamination, possibly from the feature F765, the stone dump north of the midden. So, we see a change from mainly medieval pottery to late medieval/early post-medieval pottery (below, top left – bottom right), and a mix of medieval and post-medieval pottery dating in the layer associated with quarrying .

Most of the post-medieval pottery comes from the top two features. This pottery tells us that the site was in use from the medieval period through to the early post- medieval period and the pottery sequence, including clay pipes, seems to go right up to the eighteenth century and the time when it was quarried.

 

References and Further Reading:

  • Harris, E. C. 1975. The stratigraphic sequence: a question of time. World Archaeology 7 (1): 109-21.
  • Harris, E. C., Marley R. Brown and Gregory J. Brown, (eds) 1993. Practices of Archaeological Stratigraphy. Academic Press
  • O’Carroll, F. 20 11. ‘Interim Report, Archaeological Research Excavations at the Black Friary, Trim, (Unpublished report submitted to the National Monuments Service).
  • O’Carroll, F. 2014. ‘Interim Report, Archaeological Research Excavations at the Black Friary, Trim, (Unpublished report submitted to the National Monuments Service).
  • O’ Carroll, F., Shine, D., Mandal, M., Scott, R. and Mullee, B. 2016. Interim Report, Black Friary Archaeological and Community Report . (Unpublished report submitted to the National Monuments Service)
  • O’ Carroll, F., Shine, D., Mandal, M., Scott, R. and Mullee, B. 2017. Interim Report, Black Friary Archaeological and Community Report . (Unpublished report submitted to the National Monuments Service)
  • Spence, C. 1993. ‘Recording the archaeology of London: the development and implementation of the DUA recording system’ in Harris, E.C. et al (eds), Practices of Archaeological Stratigraphy. Academic Press.
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Rock and Role of the Geoarchaeologist

IAFS Director Dr Stephen Mandal describes the role of the geologist in archaeological research at the Blackfriary.

As a geoarchaeologist one of my main research interests is in the use of stone in the archaeological record as a source for making tools and other material objects, and as a building material.  The Black friary was made from rock and understanding the building materials used – where they were sourced, how they were used, and why they were chosen – is an important part of the story of the friary.

The main building stone used in the friary was limestone, which is not surprising given it is the underlying bedrock of the area:  this limestone was formed in layers, laid down over 300 million years ago, during the Carboniferous Period, at a time when time Ireland was submerged under a shallow tropical sea.  Each horizontal layer (bed) is roughly 10-30cm thick and much later folding and faulting of this bedrock has given vertical joints and fractures.  This combination of depositional layering and post-depositional fracturing provided the medieval architects and builders with perfect, locally abundant, blocks to build the friary and the other medieval structures in the town, such as the castle and the yellow steeple.

The curtain wall of Trim castle; the wall was built on top of the limestone bedrock, from which the stone was sourced for the building of the castle.

During the first season of excavations at the Blackfriary in 2010, it was discovered that limestone was not the only building material used.  There were at least three other types of stone used; slate as roof tiles, red / yellow sandstone in decorative architectural pieces and an unusual and highly distinctive limestone used in the cloister columns and arches.  It is the latter that is the focus of this post.

 

The main building stones of the Blackfriary: 1. Limestone; 2. Sandstone; 3. Slate; 4. Purbeck

When the friary was systematically dismantled in the 1700s to reuse the stone to service a building boom in the town, the builders clearly encountered, but appear to have not valued, the decorative stone of the cloister arcade.  Beautifully ground and polished architectural fragments of an obviously different limestone was either ignored or, in places, used to provide a flat surface for the carting away of the ‘useful’ limestone building blocks.

Visiting the site early in that first season, Kevin O’Brien (architectural heritage expert with the Office of Public Works) suggested that these architectural fragments might be imported stone, Purbeck Limestone, from quarries in Dorset on the south coast of England.

My role in this rock story was to verify this identification, and the purpose of this blog post is to describe that process.  Whilst this stone is visually distinctive – it is a variety of colours from green to red and comprises 90-95% small shelly fossils in a very fine grained matrix, consistent with Purbeck Limestone – to confirm a source requires a more detailed examination.  This required the taking of samples to make thin slivers of the rock to view under a microscope.

To take a sample of an architectural fragment clearly requires damaging it, and to do this requires permission from the National Museum of Ireland.  A representative sample of small broken pieces of the material were chosen and a ‘Licence to Alter’ was applied for.  The application included details of the methodology to be used to take the sample and examine it, the research objective, and a justification for the damage caused.  The license was issued (Licence no. 5811), and the samples were taken to the Geological Laboratories in Trinity College Dublin for preparation.  A diamond tipped saw was used to take a small portion from each of the samples and these were fixed to a glass slide and ground down to a specified exact thickness of 30 µm, producing what geologists call ‘thin-sections’.

One of the nice by-products of the process was that the unused portions of the samples were left with highly polished surfaces, allowing us to envisage how magnificent the stone would have looked when the friary was built.

Purbeck samples, after cutting.

The thin-sections were viewed under a special type of microscope – a polarising light microscope; one of the most important tools of a petrologist (a type of geologist who specialises in the identification, interpretation and origin of stone).  This microscope differs from a standard microscope in that the light source is below the thin-section so the petrologist views the sliver of rock with the light shining through it, and the viewing plate rotates.  Importantly, the microscope allows the user to polarise the light waves; an invaluable aid in identifying the minerals that make up the rock, as different minerals behave in different ways when they are rotated through polarised and crossed polarised light.

Under the microscope, it was immediately apparent that the shell types, their alteration, and the fine crystalline matrix in which they sit are all consistent with this being Purbeck Limestone.

I am working with Dr Patrick Wyse Jackson of the School of Geology, Trinity College Dublin to record the thin-sections and compare with Purbeck source materials.  The results of this work will be published in due course, but what is now clear is that the use of important Purbeck Limestone provides an interesting piece of evidence as to how wealthy this friary was (or more accurately, its patrons were).

Further Reading on Geoarchaeology and Petrology in Archaeology :

Books / contributions to books
  • Mandal, S., O’Keeffe E. and Cooney, G.,  2016. Polished stone axeheads from Irish caves. In Dowd, M. (ed). Underground Archaeology: Studies on Human Bones and Artefacts from Ireland’s Caves.  Oxbow Press ISBN 978-1-78570-351-5. Ch 5. 103-109.
  • Mandal, S., 2005.  Petrographical assessment of stone finds from the Mound of the Hostages.  Published as Appendix in Tara, The Mound of The Hostages by Muiris O’Sullivan, 2005.  Wordwell: Wicklow.
  • Mandal, S., 1999. Petrological identifications of selected artefacts. In Woodman, P.C., Anderson, E. and Finlay, N., 1999. Excavations at Ferriter’s Cove, 1983-95: Last forages, first farmers in the Dingle Peninsula, 201-2. Dublin: Wordwell.
  • Cooney, G. and Mandal, S., 1998. The Irish Stone Axe Project: First Monograph. Dublin: Wordwell.
Peer reviewed journals
  • Cooney, G. and Mandal, S., 2000. The Irish Stone Axe Project: Sources for Stone Axes in Ireland.  Krystalinikum XXVI, 45-55.  Germany.
  • Mandal, S., 1997. Striking the Balance: The Roles of Petrography and Geochemistry in Stone Axe Studies in Ireland. Archaeometry  39 (2), 289-308.
  • Mandal, S., Cooney, G., Meighan, I. and Jamison, D., 1997. Using Geochemistry to Interpret Porcellanite Stone Axe Production in Ireland. Journal of Archaeological Science 24, 757-63.
Magazine articles
  • Mandal, S., 1996. Irish Stone Axes – rock and role of the petrologist. Archaeology Ireland 38, 32-35.
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Making sense of the un-excavated bits: Geophysical survey at the Black Friary

Ever wondered how archaeologists decide where to dig? One method is geophysical survey, which shows magnetic and electromagnetic changes underground…and sometimes above ground.

Geophysical survey is a useful tool for archaeology and many other fields as it is a non-invasive way to view three-dimensional segments of changes in the Earth’s physical properties below ground.  In archaeology, survey targets are often the small or weak ‘anomalies’ caused by human occupation. Choosing appropriate techniques for each site is key in acquiring useful results. Over two seasons, PhD student Ashely Green of Bournemouth University, carried out geophysical investigation.In this post, she tells about her research and results to date:

Ashely Green, PhD student, Bournemouth University

With permissions from the National Monuments Service  for site investigation (15R0023), I conducted two studies on the un-excavated areas of the Black Friary as part of my Masters and PhD research programmes.  The aims of the surveys were to combine previous geophysical datasets (‘legacy data’) with my own multi-technique surveys (ground-penetrating radar, electromagnetic induction, and gradiometry) to identify areas of archaeological potential and suggest new protocols for ground-penetrating radar surveys in order to acquire high resolution data and improve confidence in interpreting data.

The site was first surveyed in 1989 by Prof. William Kennedy and a team from Florida Atlantic University using proton magnetometry and earth resistance, which detect magnetic and conductivity changes in the ground relating to stone structures, areas of burning, ditches, and large ferrous objects (Kennedy 1989).  This low resolution survey provided a good outline of structural remains beneath the ground surface.

Kennedy 1989: Dot density plot of resistance data

The site was re-surveyed in 2010 by Ian Elliot (O’Carroll 2011), using similar techniques (gradiometry and earth resistance) but at a higher resolution. Results from the resistance survey improved upon Kennedy’s survey, clearly outlining surviving structural remains.

Earth resistance kit

Unfortunately, there was too much modern metal contamination to get clear results from the gradiometry survey. Due to this modern metal (ferrous) contamination, I opted to conduct ground-penetrating radar (GPR) surveys.

GPR detects changes (structures, voids, redeposited soil, stone, etc.) or boundaries in the subsurface materials; these features reflect back the electromagnetic pulses emitted by the instrument, at the ground surface.  Surveys were conducted at high resolution – surveying along lines (traverses) spaced 10cm apart for the cloister garth and 25cm for the town wall and cemetery boundary investigations, and collecting data every 2cm along those lines.

GPR results showed a number of responses of archaeological potential, meaning the responses were of similar size, shape, and amplitude to features you would expect to see on a medieval monastic site, but require validation via ‘ground-

GPR survey in action

truthing’.  Of particular interest were the ‘anomalies’ within the cloister garth – a loosely compacted (low amplitude) circular response associated with a loosely compacted linear response approximately 50cm below the ground surface, which could be a water well, and a number of responses that are the approximate size and orientation of medieval graves.  Results from other areas of the site required clarification, so a secondary electromagnetic induction (EMI) survey was conducted in the north range and across the possible location of the medieval town wall, the line of which is thought to be along the south boundary of the site (Shine et al 2016).

EMI instruments measure magnetic susceptibility (the ability for an object/material to become magnetised) and conductivity (the ability for an object/material to carry an electrical current).  The technique is useful in detecting stone structures, industrial areas, settlements, ferrous objects, and ditches.

Results from the north range were still quite ‘noisy’ due to the modern dumping, but one response of archaeological potential was noted on the magnetic susceptibility aspect of the survey: a linear, compacted (high amplitude), conductive response in the possible location of the medieval town wall was suspected to relate to the wall’s foundation. Thus far, no such remains have been identified in excavation (O’Carroll, Shine & Scott, 2016; 2017).

In 2016, surveys expanded in terms of techniques and location.  The focus became the medieval cemetery, the boundaries of which are estimated based on excavation results and landmarks within the landscape (O’Carroll, 2011, 2014; O’Carroll, Shine & Scott, 2016, 2017; Seaver, 2009).  We undertook GPR and gradiometer surveys at high resolution to increase the potential to detect any characteristic graves.

The survey results have been interpreted manually and a number of anomalies of interest were noted, but complete results will have to wait until the data has been interpreted using the automatic feature detection software, to result from my PhD research.

Where do we go from here?

The next steps, as with many geophysical surveys, are to resurvey areas of interest and unclear results at higher resolution with multiple techniques, expand the survey area, and finally ‘ground-truth’ through excavation.

 

 

Further reading:

Green, A and Cheetham, P. 2016. Poster: Reimaging the Black Friary: Recent Approaches to Seeing Beyond Modern Activities at the Dominican Friary, Trim, Co Meath, Republic of Ireland.  Department of Archaeology, Anthropology and Forensic Science. Bournemouth University
Kennedy, W 1989. An Archaeological Survey of the Blackfriary Site, Trim, Ireland. Report to the Office of Public Works, Florida Atlantic University.
O’Carroll, F 2014. Archaeological Research Excavations at The Black Friary, Trim, Co Meath – Interim Report. http://iafs.ie/wp-content/uploads/2014/06/Blackfriary-E4127-C240-Report-2014.pdf
Seaver, M. 2009. Burials at the well: excavation at the Blackfriary. In Potterton M and Seaver M (eds). Uncovering Medieval Trim. Dublin. Four Courts Press.
Shine, D., Green, A., O’Carroll, F., Mandal, S., & Mullee, B. (2016). WHAT LIES BENEATH-CHASING THE TRIM TOWN WALL CIRCUIT. Archaeology Ireland, 30(1), 34-38.
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Stained glass – from discovery to conservation

Since 2015, the IAFS has been collaborating with Cardiff University Conservation department, on the conservation of medieval stained glass from the Black Friary excavations.

The stained glass, we believe, was installed during original 13th century construction phase of the friary. It has been excavated over several seasons however, from contexts that were deposited around the time of systematic dismantling (quarrying) of the friary buildings in the 18th century. Excavation thus far suggests that the glass was forcibly removed from the lead cames, possibly hammered out, and most of the lead removed. The glass has survived in various states of repair, from flakes of degraded glass to shards with discernible colour and patterns.

The excavation strategy varies, depending on the size of the deposit; we have excavated individual sherds of glass, caches of glass, and large window fragments that include glass still contained in lead cames. The individual pieces, and caches are recovered by hand into finds trays, and kept cool and damp until all pieces from an individual context or cache are recovered.

The glass is extremely fragile, and is treated with a specific methodology, agreed with the conservation team, to ensure that it reaches the lab in the same condition, as excavated. This includes keeping the glass damp, packing it in sieved soil to prevent further abrasion, and maintaining it in a stable environment until it can be transported to the lab; we have a dedicated fridge in our on-site post ex lab for this.  The glass is also photographed, so the conservation lab has a visual reference to accompany the find record. This helps in planning the conservation process, and in assessing any deterioration in the glass between excavation and conservation.

The window fragments identified are excavated using a ‘block lift’ methodology, designed to allow the excavation and conservation of the fragment in lab conditions. In 2015, conservation staff of the National Museum came to the site to demonstrate this technique: the artefact is isolated by excavating around and below it, leaving the artefact partially exposed and sitting on a ‘pedestal’. Ideally, the artefact is excavated only enough to determine its size, leaving a protective covering of the soil matrix around it. This is then wrapped and sealed with film wrapping (cling film), cushioned with acid free tissue or bubble wrap, and wrapped again to secure this. Finally, this is secured and stabilised by wrapping it with fine gauze bandages infused with plaster – the type used to cast a broken limb! This last bit is a slightly messy process that involves immersing the bandages in a basin of water, and immediately wrapping it around the prepared artefact to ensure that it is secured in place before its starts to dry out. Several bandage wraps might be required to fully stabilise the object. Once the bandages have dried and hardened, the block can then be lifted. This last step requires that the block is carefully levered up, and a prepared board slid underneath it to lift it. Depending on the size and weight of the finished block, this is in then further wrapped, or boxed and sealed, to ensure its safe transport to the conservation lab. When in the conservation lab, it can then be excavated in controlled conditions by the conservation team.

Our first batch of glass was sent to Cardiff, under licence to export and alter from the National Museum, in late 2015. Post graduate conservation students have been working through the collection, and have almost completed the initial conservation, moving now to XRF and SEM analysis. We are really excited to see the finished pieces and to hear the results of the analysis.

Follow the story of the glass on the Cardiff University Conservation Blog, by research coordinator Meredith Sweeney:

What happens when 239 boxes of stained glass and lead are brought to conservators? We buy fridges!

Looking Through the Window Glass

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Using 3D Lasers in Archaeology: Trim Castle project

3D Digital Scanning at Trim Castle: OPW Archaeology Talk

On Thursday June 30th, the OPW office in Trim will host a presentation on the current 3Dlaser scanning project at the National Monument sites of Trim Castle and the Black Friary, Trim, Co. Meath.

Dr. Rogers and students laser scanning Trim Castle

Dr. Rogers and students laser scanning Trim Castle

Professors Michael “Bodhi” Rogers of Ithaca College and Scott Stull of SUNY Cortland in cooperation with the OPW are conducting a 3D laser scan at these sites, using state-of-the-art scanning equipment.

The presentation will describe the results of this research and its application in advanced interpretation, conservation and preservation at the sites.

Rogers and Scott have collaborated on several projects combining archaeological excavation, geophysical archaeology, and 3D laser scanning including several landmarks in the United States, including Abraham Lincoln’s cottage in Washington D.C. and the Old Fort Johnson National Historic Landmark in Johnstown, New York.

The results will help inform future strategies for investigation, interpretation, and preservation at these sites, including on-line access to the archaeology through imagery generated by the scans, and advanced detailed recording techniques, preserving the site digitally for future generations.

“3D laser scanning is an emerging technology that facilitates digital preservation of standing structures,” said Rogers. “Our scanner pulses 50,000 times per second to take a reading every five millimeters. By moving the scanner around the site, we’ll create a full digital record that can be used to facilitate historic preservation planning, create virtual tours and aid in repairing any future damage to the structure.”

 “Our research at Trim Castle will be the largest historic structure we’ve laser scanned, which will provide us with interesting new challenges,” said Rogers.

Professors Stull and Rogers and the IAFS team will also collaboratively mentor students as they perform geophysical archaeological surveys and archaeological excavations at the Black Friary site.

The presentation will be on the 30th June 2016 at 6pm sharp in the Atrium in the OPW offices, Jonathan Swift Street, Trim, Co. Meath.

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Winter 2016: Lauren reports – last post from our intrepid intern

In the eleventh – and final – in a series of weekly blogs, IAFS/Learn intern Lauren Nofi reports on the last week of her internship.

This is what Lauren looks like underneath her hat and coat and 20 layers – she just has to visit in the summer:

Hello! This past week we’ve been getting some last bits of information needed for the site report as well as working on the site archive in general. Of course the weather was beautiful when we were sitting in the site office. Many a time I had to physically wrestle my intern (Ciarán) from sneaking out of the post-ex lab with a trowel…he claimed he heard a song coming from the trenches telling him to come to the main work area of Cutting 6 where our chapter house stood. My only explanation for this sudden and belligerent behaviour is trench sirens which are a thing I totally did not just make up. Trench sirens, like sirens of the waters of the ancient Mediterranean, call me to their doom with sweet songs. And I’m like, “Ciarán, bro, do not go into the trench. You’re going to your doom.” So aside from all of this doom, we had a very pleasant week of office work.

Our last bits of research were gathered and sent off to Dr Shine who had the herculean task of writing the main body of the site report. We were mostly just checking paper records for feature descriptions and putting together little cheat sheets of trench info. After this, we went through our old paper records and undertook a number of archival tasks.

We pulled out all the folders of every plan of every trench on site and went through them, cleaning up any rough edges, remnants of masking tape used to hold them to drawing boards, and checking their contents. We compared our drawing register information with what was actually written on each drawing sheet, adding grid points or supplementary information from our register. It was very interesting work as it allowed us to see areas of the site we had only known as backfilled cuttings as well as giving a glimpse of earlier phases of our two cuttings from this season. Soon all of these plans, section drawings and profiles will be scanned for the computer to add to our digital record of the site. I’ve talked about plans more than you probably ever needed to know, but section drawings and profiles are the other drawn records we take of spatial elements: section drawings are like cross-sections of an excavated area, while profiles map the elevation changes of a given area of trench.

After this, I began digitising all the old trench files while Ciarán chased down some specifics on our “show and tell” box of finds. Every cutting has a folder full of feature sheets, describing every feature within each cutting, as well as various registers and other notes. I started the process of scanning every page, compiling multiple sheets into PDF files for each feature, and converting them to an archive-quality PDF. Just like with paper records, one of the most important parts of creating and storing an archive is thinking ahead about how these physical materials may degrade over time. With our paper documents, we have to think about things like ink fading, or binder holes ripping, and things like storage conditions. For our digital documents, we have to think about how we will access them in future, so for example, we are using a type of PDF which will still be able to be viewed even if PDF reader technology improves and computer programs change in the coming decade. It’s all a lot to be conscious of, as our archive itself becomes like an artefact we have to conserve.

It’s my last week on-site, and I just wanted to say a quick thank you to everyone who made it possible for me to be here doing the stuff I love. So thanks to all the staff for helping me to become a better archaeologist; showing me the ins and outs to running both a site and field school. Thank you to all the amazing students who helped me become a better teacher, as y’all are one of the main reasons I love working at field school. Finally, I’d like to thank all of you who read and shared this blog; I honestly never thought my words would reach as far as they have, and it’s been an honour to be your host for our very first winter season at the Blackfriary. This whole experience was unforgettable, so from the very bottom of my heart, thank you all.

Lauren

 

 

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No expense is spared for Lauren’s goodbye!!! Tasty AND tempting, food at ‘Supermacs’.

Thank you so much for all the hard work, and for doing this incredible blog. We are really going to miss you Lauren. Come back soon – Denis, Fin, Ciarán, Mairead, Bairbre and Steve xxx

 

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Winter 2016: Lauren reports – numbering, labelling and digitising

In the tenth (and penultimate) in a series of weekly blogs, IAFS/Learn intern Lauren Nofi reports on the progress in the post-excavation laboratory, looking at ceramics and the process of data entry:

Hey hey, this week was all about finishing registering and processing our last bits of LN Blog 1ceramic as well as completing quite a bit of data entry. The last part of our processing of ceramic fragments involved some nimble fingers and a lot of patience…come to think of it so did all the data entry as well.

The site is rich with ceramic material, mostly in the form of pottery, though occasionally we get tiles and unidentifiable bits of fired clay. This pottery spans the entire occupation of the site, so we generally categorise our sherds as either medieval or post-medieval. This is a common practice on sites with multi-period use, and allows specialists to more easily find the physical artefacts as well as trace trends within the spatial use of the site through time. Every single fragment we have, just as with other artefacts, is assigned a unique number. This number includes the site code, feature number, and artefact number within said feature. For artefacts made of metal, we simply place a permatrace tag with each specimen. For pottery and tiles, however, we write our number directly on the sherd.

Stone and worked shell artefacts receiving tags, medieval pottery (first two), post-medieval pottery (second two), pipe bowl (centre top), pipe stems

Stone and worked shell artefacts receiving tags, medieval pottery (first two), post-medieval pottery (second two), pipe bowl (centre top), pipe stems

The actual process of pot-marking is simple enough in theory, but once you actually start working you’ll see it takes a special kind of archaeologist to really excel at labelling efficiently and legibly. I am not this type of archaeologist 🙂

The first step to labelling a ceramic item is to inspect it for any special decoration or feature, something diagnostic (like whether it is from a rim or base. You can even determine the original size of the mouth or base of a vessel with these diagnostic pieces and a bit of maths). You definitely don’t want to write your artefact number on, say, the only visible bit of glaze since this later may be necessary for identification, or, even in some cases, reconstruction. Ideally, you would be writing the number along an edge on the inside surface of the vessel, which allows future display or reconstruction to be relatively unaffected by your labelling system. Sometimes it’s just not possible to determine an inner surface from an outer, or the shape of the sherd doesn’t allow for easy writing.

Tools of the trade: acetone (glass jar), varnish (tin), special and practically magical tiny-nib pen, and some brushes

Tools of the trade: acetone (glass jar), varnish (tin), special and practically magical tiny-nib pen, and some brushes

Once you’ve found a surface to label, you must place a thin strip of a special multi-purpose fixative: it’s basically a varnish, consolidant and glue all in one which conservators call Paraloid B72. When this dries, you add another layer of varnish. You’ve now made a writing surface which is removable, as reversibility is incredibly useful. This particular varnish can be removed with acetone, so if something must be re-labelled, a quick swipe of acetone and gentle scrub gives back your original ceramic surface no worse for wear. Next, you use a pen, often a specialised one with a very thin nib, to write your artefact numbers on your varnish stripe. One final coat of varnish and your find is now identifiable.

This is the teeny tiny pen nib

This is the teeny tiny pen nib

Fellow intern Ciarán and I developed a nice little assembly line of artefacts in various states of labelling. I handled the measurement for registering and varnishing, while he entered the measurements into our digital ledger and wrote the actual numbers.

Voila! A labelled potsherd

Voila! A labelled potsherd

I should say it wasn’t just potsherds and tiles in our ceramic collection, I did leave out my favourite type of object: clay pipe fragments. They are my favourite simply as nearly every site I have worked on has amassed nice collections of pipe stems and pipe bowls. These functional and occasionally even decorative objects begin their historical life in the colonial period of Britain concurring with the tobacco trade. Some specialists have actually used the dimensions of the pipe stem bore-hole and the bowl as markers for dating the artefact; in general, smaller bowls are often earlier due to the very low quantities of tobacco available in the first centuries of the industry. By the 1790s, clay pipes were also made into extravagant collectors’ items, with multicoloured glazes and extended hollow chambers. One type of these decorative pipes is known as Prattware and some feature comical heads and bodies curving to form the stem and bowl. Some of it is truly hideous (so naturally I love it). Our simple clay pipe fragments however have contemporary analogues all over the world, especially wherever the British tobacco industry reached (yes, I know we are in Ireland, but you have to think of major players in the beginnings of globalised trade and the influence of British law and socio-economics on Ireland).

Some pipe stems freshly labelled

Some pipe stems freshly labelled

My other work this week involved lots of computer work. I spent some time populating tables for all our cuttings listing the artefacts and ecofacts found therein for our upcoming site report. In addition, I collated information on all of our outreach activities since our founding as IAFS, also for our report. Lastly, I digitised our burials register, creating a searchable spreadsheet of all of our articulated inhumations.

 Until next week!

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Winter 2016: Lauren reports – metal artefacts

The ninth in a series of weekly blogs, IAFS/Learn intern Lauren Nofi reports on the progress in the post-excavation laboratory, looking at the collection of metal objects.LN Blog 1

Hello, hello, hello! This week we’ve been continuing in post-ex, cataloguing and sorting our finds from the summer and our recent winter session. We’ve been updating our catalogues and labelling objects as necessary, as well as checking and cross-referencing different registers. The infant burial I was working on has dried and been re-bagged and packed according to our burial storage procedure.

Some of the material we were sorting and labelling this week included window lead. We have a separate register just for window lead, but sometimes lead was identified as simply a lead object and registered with our general bagged finds. We had to ensure all the bits of lead used to support window glass were properly noted both on their bags and their locations were traceable through the registers’ entries.

How window lead appears when excavated, though often in much smaller fragments

How window lead appears when excavated, though often in much smaller fragments

The bits of lead used in window glass are called “cames.” Now I know some of you are probably thinking, Homegirl, why do you care so much about scraps of lead from windows? Well, homedawgs, let me tell you a little story about the importance of window lead:

Once there was a very important and well-known Colonial American site which shall remain nameless since this is a tale of archaeological horror. They found so much lead in the form of crushed and warped cames, the individual pieces were recorded as simply a bulk find and shortly discarded. One day, after over a decade of simply discarding their window lead, an archaeologist with a mind for conservation carefully pried open the tiny flaps (each called a “leaf” and which would have secured the piece of glass). The window cames would normally look like the picture above, but the crushed cames would have the small wings overlapping the glass sealed together.

A lead came with a double-channel forming an H-shape when viewed from the ends

A lead came with a double-channel forming an H-shape when viewed from the ends

The main channel of the came revealed a surprise: the maker and year was embossed within the lead. It just so happens the English lead workers had jointly enacted a set of quality control regulations requiring all lead to be marked with maker information, so if it failed, the proper action could be taken with regard to suppliers. Suddenly, a whole new source of historical information became available though it has likely been there all the time, in the thousands of discarded lead strips. The window cames allowed archaeologists to date the construction phases of colonial buildings in the area to within a few years!

Now to be clear, I’m not saying our window lead is even from the same century as my little tale above (ours is usually about three or four centuries older), but I just wanted to explain how a very simple object can open up the history of a site unlike any other. So I’ll never scoff again at the care with which some bulk finds are recorded, and I know I am much more open to post-excavation work to err on the side of hoarding. Not that everything must be, or even should be, saved, but you never know what technological or analytical breakthroughs may be made in a few years’ time, so keep your mind open but be judicious regarding what bulk material you save.

An intricate lead came with a floral motif

An intricate lead came with a floral motif

In addition to lead, we also had copper, iron, and glass, artefacts to catalogue or update entries in our registers. Some of our iron is immediately identifiable, even with its bulky rust. Iron usually corrodes and forms brown and orange-y concretions of oxidized material, which basically means it rusts and unevenly gets a little bigger due to the process of rusting. Copper and its alloys, however, often corrode anywhere from a bright green to a forest green, depending on the presence of other elements. There are of course many different types of corrosion encountered with metals in archaeological contexts, but these are often the most common and the most easily identifiable corroded metals. Glass corrodes differently, as it begins to break down into incredibly thin, brittle layers in a process called lamination. The materials in the glass itself, along with this splitting of layers, often produces iridescence. These layers each refract, or bend, the light which splits it into many colours. If you were to place glass laminated in this manner in water (DO NOT if it is archaeological, I’m just saying if you were to) the water would fill in the very tiny air holes between layers and allow most light to pass back through. This is why when you are (carefully) washing archaeological glass, it sometimes looks un-corroded temporarily.

Our next task is to register and pot-mark (literally write finds numbers on) all the ceramic material still in post-ex. I’ll talk a bit about pot-marking in next week’s blog. So long!

I found this iron key amongst our artefacts, the very key to fellow intern Ciaran’s heart. It’s old and crusty just like him

I found this iron key amongst our artefacts, the very key to fellow intern Ciaran’s heart. It’s old and crusty just like him

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Winter 2016: Lauren reports – more PEX!

In the eighth in a series of weekly blogs, IAFS/Learn intern Lauren Nofi reports on the progress in the post-excavation laboratory.

Hello, all! Briefer blog this week as we are still washing in post-ex!

Last week I wrote about all manner of bone-washing. This week we continued and finished cleaning all of our disarticulated human bones and sought to also process our animal bone excavated during this winter season.

One particularly exciting part of examining our animal bones as we wash them is when come across signs of butchery or other consumption via cut marks. Even fellow intern and historian Ciarán was quite tickled to come across any of these signs, which only means one thing: HE’S ONE OF US (ONE OF US, ONE OF US). This is a particularly nerdy archaeological thing to get excited about, but ask anyone working with animal bone in an analysis context, and they’d probably say the same. There’s just something cool about holding in your hand someone else’s dinner from nearly 800 years ago! Unfortunately I couldn’t get a good photograph of cut marks, just due to the lighting, but if I come across a particularly aesthetically pleasing example I will post it.

Some of our animal bone drying

Some of our animal bone drying

We had one feature which produced so much animal bone in our brief winter season it took several crowded drying racks just to accommodate it all! In the previous pictures you can see fairly robust bones and fragments, but sometimes we were working with much smaller quantities.

A small portion of our largest animal bone sample of the season

A small portion of our largest animal bone sample of the season

At our site, animal bone is considered a sample. Samples are taken for a few reasons, but most often for statistical or specialist analysis.

Some smaller animal bone samples

Some smaller animal bone samples

Notice the tags have numbers in a diamond or lozenge shape. This is how at a glance we can know whether the bones we are encountering have been classified as human or animal, since, of the two, only animal bone receives this designated shape. Recall our disarticulated human remains all had a specially assigned DHB number. Similarly, our animal bone samples will all have a sample number which relates to the cutting from which it came.

In addition to working with all this animal bone, I started washing some material I found quite moving: an infant burial. The bones themselves are ever-so-delicate and really require a soft touch. The process itself is slightly different as the excavators kept associate bones together, so I have bags for each hand, each arm, each leg, and so forth, to clean and let dry separately. (Once dry this will all be packed both to simulate the order of bones in the body but also allow the more fragile bones like the skull to be kept from damage.) Naturally I was briefly petrified as I picked up the very first fragment of cranium. Even though I have obviously worked with human skeletal material before, this has so far been some of the most difficult work. Not only does it necessitate fine motor skills, but the entire process sparks another mini-existential crisis like I mentioned last week over the tiny person in your hands. It reminded me that human bone was once part of a person; seeing, thinking, feeling.  With that in mind, we always treat human remains with the utmost respect.

 I’ll keep you all updated as I finish this, and we begin working with some of our worked artefacts.

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