Trench One, Week Four Update – Bamburgh Castle

 

This week in Trench One we starting digging the test pit which we discussed in our last blog post. During excavations we identified a feature running east to west which showed as a dark patch running across the sondage with 4-5 vertically standing stones within it.

 

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Test Pit A.

 

Also uncovered were at least two areas of burning which may possibly be related to the early timber palisade defence wall of the castle, but the evidence is currently inconclusive.

Excavations have revealed a grey patch, a pit dug on the robber trench, closer to the south edge of the trench, which is filled with rocks. It can be seen in section on the east wall of the test pit.

 

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Test Pit A – facing St Oswalds Gate.

 

A second sondage was dug (measuring approximately 20x40cm and 60-70cm deep) in order to see if we could reach the bedrock and determine the depth of the natural boulder clay. This extent has not yet been reached.

The plan for the next couple of weeks is to identify 2-3 areas of interest to dig small sondages through to the bedrock. Digging out the whole trench would take far too long and too much effort when targeted depth investigations will suffice.

On a side note, the kiln has very nearly been completed and only one more layer remains within the kiln.

 

Bamburgh Castle, Trench One Update.

Welcome to this Trench One update!

Test pit A (as mentioned in the week 1 interview video) has now been set up and we’ll keep you posted as progress continues.

 

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Test Pit A extending north-south across the width of Trench One.

 

We found the construction cut for the 12th/13th Century curtain wall and it contained a number of pottery sherds, mostly green glaze. It was also the source of the ‘mystery’ clay circular objects which we tweeted last week. One possible explanation of them was bungs scored into unfired ceramics which then popped out during the firing process.

 

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Unidentified clay objects. Any thoughts?

 

Underneath the rubble foundation of the curtain wall we have an earlier (possibly 8th/9th Century) masonry block with adhered mortar associated with two others, which may have been used as the  backing corner of the kiln.

Last week in Trench One the kiln was sampled as planned. It looks like it was damaged and/or broken with use quickly discontinued – there is grain still in situ in large quantities, and the upper fill layer appears to be a ‘demolition’ context with extensive CBM fragments from the body of the kiln. In the video below Sam Serrano, Trench 1 Assistant Supervisor discusses the kiln and its excavation in more detail.

 

Work has also continued excavating half-sections in various small features, post-holes and pits to help add to the stratigraphic sequence and story of Trench One.

 

Bamburgh Castle, Trench 1 – Week 1 Interview

In this video Sam Serrano, Trench 1 Assistant Supervisor, discusses progress in the first week of the season and what’s planned for the coming weeks.

Stay tuned for further videos and updates here and on our YouTube Channel as the season progresses!

And so it has begun…

Week one is well underway here at Bamburgh Castle and things are picking up for the 2016 dig season!

Trench One

Trench One was left uncovered over the winter and allowed to weather and next week the students will begin investigating whether this exposure has revealed any discrete features or contexts not previously visible.

This week, excavation began around the base of the Medieval curtain wall at the kiln feature in preparation for photogrammetry. Once the photogrammetry is complete the feature will be sampled for environmental processing.

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Trench Three

Trench Three is almost completely de-tarped and cleaning has begun in preparation for the start of season trench photo. This cleaning removes the washed in silt and weathering from the past 10 months from the surfaces and features within the trench, including wall slots and the 1970s test pit from Brian Hope Taylor’s excavations.

The trench has already yielded its first small find – a possible metal stylus uncovered by student Ayesha.

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Post-excavation

The Finds and Environmental department has been hard at work this week getting ready for the season and updating the databases. The flotation tank is pumping, and everyone seems to be enjoying it.

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As part of our traditional introduction to the site, students started the week washing bulk find material from last season. This helps to introduce them to the stages of post-excavation processing, and familiarises them with the common artefact types and materials found on site – very helpful when they begin excavating!

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More news on the way soon!

A confused person’s guide to Trench 1

We thought it might be helpful, for regular users of the blog, to put up annotated photographs of our two trenches, as I am sure at times it is difficult to imagine just where the individual buildings and features lie. In this blog we will start with Trench 1.

Trench 1, labelled to identify the key features, facing north

Trench 1, labelled to identify the key features, facing north

As regular readers will be aware, Trench 1 lies at the northern tip of the fortress, at the lowest point of the bedrock plateau. Here we have unearthed evidence of the early phases of defensive structures built in timber together with a rather substantial timber hall. On the photograph you can see this as a shaded outline with the outline of a later stone hall superimposed on top of it. It is perhaps only when you outline it so clearly that its full scale becomes apparent. As we have described before it completely dominates the gate cleft (in the bedrock) to its south-west, which is the earliest known entrance to the fortress.

The stone building has been assumed to be the later of the two, but it is only this season, whilst investigating the area where the two structures come close to each other in the north-east corner, that we have proved that this is indeed the case. The date of the stone structure’s construction is uncertain, but it appears to have been robbed out before the Norman Conquest.

We are on less certain ground on the western side of the trench where we have a massive laid stone boulder foundation, for what we believe to be a timber wall, that we are interpreting as part of an early phase of defences. This is based on its general alignment with the break of slope of the bedrock, and the presence of a large timber post-setting that could have carried an archway across the gate cleft itself.

The later medieval defences are much better understood, as we have written records surviving from the 12th century to help in our interpretation. The later medieval gate is built in two phases, the first dating from the later 12th century with a 13th century widening, presumably to carry a breteche (an extension like a balcony built over a gate, with openings in its base to shoot projectiles or drop objects through). The gate widening and breteche are likely to be contemporary with the glacis built in front of the gate that we have no direct dating evidence for.

The tall stack of surviving medieval curtain wall that survives on the northern wall line would once have extended all the way around the seaward side of the West Ward, just as the 20th century wall does today.

When is a Sunken Featured Building not a Sunken Featured Building?

Sunken featured building (SFB for short) is a term used in early medieval archaeology alongside the German term Grubenhaus (plural Grubebhauser) to describe a particular type of small to medium sized timber building, constructed in northern Europe from the 5th to the 12th century AD. Such structures are part of a tradition of buildings with sunken floors, or partially subterranean elements, that span thousands of years of use. In this wider sense the term pit-house (Pit-house) is often used.

A reconstructed SFB or Grubenhaus at Bede's World (Wiki commons)

A reconstructed SFB or Grubenhaus at Bede’s World (Wiki commons)

In Trench 1 we have been referring to traces of a structure in the SE corner of the trench as an SFB. In this case we have been using the term as short hand, as although the structure is slightly sunken into the ground, it does not have many of the characteristics we would expect of an early medieval SFB. They tend to be relatively easily identified as cut features, although often eroded. Ours, though broadly rectangular, is quite difficult to define and seems to have been formed from erosion of a floor rather than having been deliberately dug. Also classic SFB’s tend to have post-holes located centrally to the short walls, indicating a gabled roof. Our feature, so far, appears to have a central post, supported by a re-used quern stone.

Our rather amorphous, sunken floored structure is shallow and less than distinct compared to a classic SFB.

Our sunken floored structure is shallow and less than distinct compared to a classic SFB.

Other factors also place our enigmatic feature outside of the general tradition. It is not associated with an industrial or workshop area. That lies in the area of Trench 3. Most of all, SFB’s are found on very different subsoils, such as sands and gravels, where excavation below ground level is a relatively easy option to increase the internal volume of a building. Our strange feature lies on boulder clay, which is pretty difficult stuff to dig. Ask any of our excavators!

In the next few days we should have excavated the last of the material within the hollow. Already we are seeing what appear to be features beneath it. The interesting question will be, are these features associated with the overlying structure, or a new phase of activity beginning to show up.

Trench One’s sunken featured building slowly reveals its secrets

The SFB under investigation

The SFB under investigation

Regular readers of the blog will recall that we have been investigating a sunken feature building (often called an SFB for short) in the south east corner of Trench 1 Some new evidence for our ellusive sunken featured building within Trench 1). Its broadly rectangular shape is formed from a shallow hollow in the ground, very likely the result of a deliberate structural cut, filled with a grey-brown silt with a substantial stone content. SFB’s are common on early medieval sites, but tend to be found on subsoils such as sands and gravels, that are easy to dig into, rather than the much more intractable stony boulder clay we have at the base of Trench 1. This makes us a little cautious about our interpretation of the feature at the moment and we would not be surprised if further investigation leads to new twists in the story.

The newly identified quern stone we believe was re-used as a post support

The newly identified quern stone we believe was re-used as a post support

Earlier we identified, what we believe to be a socketed stone that was well sited to be a central roof support. This interpretation of the stone’s final role appears to be still valid, but further investigation has revealed that its a broken, or roughed out, upper stone of a rotary quern. In addition we have two sherds of pottery associated with the feature. Both have an incised decoration on the outside of what is a course fabric. At the moment we are assuming that these sherds are early/middle Saxon in date. Hopefully the decoration will allow a specialist to date them a little closer than we can at the moment.

The to sherds of pottery, decorated by incised lines. Whilst not joining fragments, they may be part of the same vessel

The two sherds of pottery, decorated by incised lines. Whilst not joining fragments, they may be part of the same vessel

 

More things making sense in trench one

Today we enlisted all of the students at the castle in moving hundreds of kilos of dirt off of the tarps in trench one. This northern section of the trench hadn’t been uncovered in years so had accumulated much growth.

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Mattocks?! In trench one?!

We believe that we have identified the relationship between at least two post-pit which fit into a general pattern of such features in the wider trench. One area that has been causing much confusion is a join between a construction cut and a robber trench. Here we were hoping to identify a stratigraphic relationship between the two, but it now seems someone dug a stone filled post-pit right through the two features. Frustrating but at least we now know.

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You can see the two trenches end in a pit.

Exploring around the socket stone

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Cleaning away all the green in trench one

We were a bit rained out here at the castle on Wednesday though we did manage to get a good chunk of planning done in trench three yesterday. Trench one has spent the past few days digitizing some of the records from last year and today they have been exploring the area around our newly discovered socket stone.

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Allie and Shuang exploring the area around the socket stone.

 

Some new evidence for our elusive sunken featured building within Trench 1

Last season we were pretty sure that we had identified a sunken features building on the south side of Trench 1. Not necessarily a Grubenhaus, but something with a sunken or eroded floor. We were struggling to properly identify its sides then, but a little winter weathering seems to have helped, and we now have a pretty good rectangular plan. Best of all we have just unearthed a socketed stone, right in the centre of the structure, that almost certainly carried a post to support the roof.

The dark stain marks the general area of our sunken structure

The dark stain marks the general area of our sunken structure. The pivot stone is visible in the area under excavaation.

A closer vew of the socket in the stone that we believe marks the base of a post that supported the roof.

A closer vew of the socket in the stone, that we believe held the base of a post that supported the roof.