Caerlaverock and the impact of Medieval storm surges

As Drs Richard Tipping and Eileen Tisdall along with Dr Tim Kinnaird of St Andrews return to Caerlaverock to carry out their final piece of field work this Saturday (2 October), Richard Tipping discusses what has happened so far.

Background

Earlier blogs have described the fieldwork, over the summer, at the Old Castle at Caerlaverock in south west Scotland. We have been testing the idea that several very large storm surges impacted the castle, persuading the occupants to re-build, higher up and further inland. That fieldwork involved recording sediments in the moat (Figure 1) and surrounding ditches, confirming that these sediment traps are full of silt derived, we think, from storm surges pushing sediment from the coast, through the harbour and into the moat. We’re checking the origin of the silt from diatom analyses, which can define water salinity. But we hadn’t found evidence that these storm surges were destructive, impacting archaeological features. Now we think we have.  

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Setting

The ‘park pale’ is the name given to a ditched-&-banked enclosure that extends west from the harbour at the old castle for several hundred metres (Figure 1). It was constructed along a small cliff that marked the medieval coastline, separating mid-Holocene estuarine sediment, called ‘carse’ to its north and a series of very broad, parallel east-west trending ridges and basins constructed by medieval storm surges to its south (Tipping and Adams 2007).

Figure 1. Natural and archaeological features near the ‘park pale’ at Caerlaverock.

In Figure 1, a LiDAR image, Ridges 9 and 10, and Ridges 15 and 18 are seen. Between them, lagoon basins were trapped: Basins 8, 3 and 4 here. Some basins will be radiocarbon dated because peat formed when they were isolated from wave action. 

In detail (Figure 2) the ‘park pale’ is complicated. There is an inner bank to the east, with a crest around a metre higher than the ground to its south. This is lost at a 25m wide gap and cannot be traced further west. Instead, a second, lower outer bank continues north west to the New Castle Burn (Figure 1). The outer bank has, in places, an outer and inner ditch. Another, 4m wide gap may be what Brann (2004) thought was an entrance.

Tr 3 (ii) is the line of a 50m long sediment-stratigraphic transect of 24 hand-sunk boreholes from the ‘carse’ in the north, which the inner bank rests on, south across Basin 3 to the canalised Old Castle Burn. The transect was designed to test the idea that the 25m gap in the ‘pale’ is an erosional feature from storm surge impacts.

Figure 2. Features around the distinctive 25m wide gap in the ‘pale’

Stratigraphy

What Tr (ii) shows is that the low ground of Basin 3 is floored by bedrock less than a metre down. This is covered by well-sorted sand and then by poorly sorted coarse to very coarse sand and grit with common pebbles.This fills Basin 3, thickening shoreward. This is interpreted as a storm surge deposit, deposited in a high-energy marine environment. Boreholes on the inner bank, a metre higher than Basin 3, and 25m inland, also recorded thick gravelly sand, impenetrable at 90cm depth on the inner bank. This thins north but is still found 20m inland from the medieval coastline.

Narrative

There were at least two storm surge ridges formed before the events recorded in Basin 3. Basin 8 (Figure 1) was formed by the second storm surge, as yet undated. This created Ridges 9 and 10. These broad gravel ridges in turn protected the western ‘park pale’ from subsequent marine erosion (Figure 2). What is now the outer bank, with its associated ditches, probably represents the original boundary of the ‘pale’. The ‘pale’ pre-dates the storm surge event described here. It is shown by the sediment stratigraphy to be, broadly, medieval in age and, broadly, contemporary with the old castle.

Eastward, Ridges 9 and 10 merge with the ‘carse’ of the medieval coastline, leaving this part of the coast vulnerable to later storm surges. At this point, the outer bank of the ‘pale’ is lost. In its place are storm surge sediments. The ‘pale’ was eroded by the storm surge. This storm surge pushed at least 90cm of gravelly sand north onto the surface of the ‘carse’. The cliff may have been formed after this storm surge, by later erosional wave action. Gravelly sand was pushed or thrown 20m beyond the cliff. Waves also scoured the easily eroded ‘carse’, lowering the surface by around 0.5m, up to 100m inland.

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References

Tipping, R. and Adams, J. 2007. Structure, composition and significance of medieval storm beach ridges at Caerlaverock, Dumfries & Galloway. Scottish Journal of Geology 43, 115-123.

Old Wick: Removing the Joist

On Wednesday and Thursday 22nd and 23rd of September, a team lead by Rachel Pickering of Historic Environment Scotland and Coralie Mills undertook to remove the remains of wooden joist from the keep at Old Wick Castle. The joist hole was 8 metres above ground level. If successfully removed the joist was then to be taken away for testing and hopefully provide a date for it and the castle. In a slightly different blog than usual here are three short videos looking at how the removal process went.

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Below Rachel Pickering and Coralie Mills on day one explaining what they have found:

In the second video we see Coralie Mills and her colleague Hamish Darrah attempting to remove the joist from its socket

While in the third video Coralie and Hamish give their initial thoughts on the newly extracted joist:

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All videos courtesy of Rachel Pickering of HES.

Testing time at Castle of Old Wick, Caithness

As the Old Wick project gets underway, the project lead Rachel Pickering of Historic Environment Scotland explains what they are trying to find out and how.

In the far northeast of mainland Scotland, on a narrow promontory, surrounded by cliffs on three sides, stand the ruins of Castle of Old Wick. The castle is one of Caithness’ most striking medieval sites due to its rugged location. But time has not been kind to the castle, and all that survives above ground is the stark stone skeleton of a once grand tower, within low-lying earthworks on the promontory behind. There are many unanswered questions about this castle, not least ‘when was it built?’.

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Castle of Old Wick in its dramatic coastal setting. © Crown Copyright HES

Very little is known about the castle’s origin and development – there is limited documentary evidence relating to its earlier history and no diagnostic architectural features survive, making it very difficult to date. It was once thought to have been one of the earliest stone castles in Scotland, associated with Norse earls of Orkney and Caithness. However, more recently, scholars have questioned this, suggesting a 14th century date is much more likely for its construction.

Reconstruction illustration showing how the castle and its surrounding outbuildings may have looked at its height. © Crown Copyright HES.

One tantalising clue survives that may shed light on its construction history – a single fragment of timber within a joist socket of an upper floor. The image below shows these joist sockets which indicate the tower had timber floors throughout. The sole surviving timber is increasingly at risk of decay as it is exposed to the elements. Our aim is to remove the timber and assess it for dendrochronological analysis – or tree-ring dating, before conserving the remains. From this we may be able to get a scientific date to indicate when the castle was built. At the very least, such a date may provide an age and provenance for the timber joist which provides an insight into phases of the castle’s development.

Interior of Castle of Old Wick showing joist sockets indicating the location of first and second floors. © Historic Environment Scotland.

Thanks to generous grant funding from the Castle Studies Trust, HES and specialist contractor Dr Coralie Mills of Dendrochronicle will be carrying out new research this autumn, with the hope of recovering dating evidence.

The timber is believed to be oak, making it suitable for dendrochronological analysis, though it is in a very fragile state. It will be accessed using a scaffold and very carefully removed and wrapped before being transported to the laboratory in Edinburgh for detailed examination. Its condition and suitability for dendrochronological analysis will then be assessed. If it is not possible to analyse the rings of the timber due to its condition, then an alternative method will be undertaken using radiocarbon ‘wiggle matching’. This would involve taking several samples for high precision radiocarbon dating, allowing for a more accurately calibrated radiocarbon date for the timber.  

We hope this research will shed light on the construction and development of Castle of Old Wick, by providing valuable scientific dating evidence. The project will also potentially support the on-going development of dendrochronological analysis within Scotland, as every new analysis can help to add to and refine existing tree-ring chronologies, which in turn supports future research.

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Richmond Castle Excavation Day 17: Another Trench! (and some more cameras)

Excavation Director Jim Brightman of Solstice Heritage gives an update from the end of Wednesday 4 August

With things now very firmly heading towards the end of the excavation, we were able to arrange our logistics just right to let us to open a fourth trench on Monday. It was always our hope that we would be able to get to this point, though with the volume of archaeology (and more recent backfill) in our first three trenches, it’s been very much up in the air as to whether we would have time.

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Fortunately, Trench 2 was completed, and we were able to set to de-turfing an area very close to the southern wall of the Castle and around some slightly enigmatic wall footings that had been consolidated and left above ground in the mid-20th century. It is not entirely clear what these walls might represent, and it has given us another bite at potentially locating the medieval chapel which we were hoping might have been in Trench 3.

Although we are only a short way through the topsoil, we have already seen a real mix of finds from all periods of the Castle’s history: bits of glass and pottery potentially from the Victorian and World War I occupation, some lovely pieces of medieval pottery to show we were heading in the right direction and even a bullet casing made in 1974. What that was doing in the Castle, we have no idea!

The real star of Trench 4 (featured image) so far, however, has been the fragmentary remains of a really fine plaster or lime mortar floor—a hint that we may well be within the footprint of a well-appointed building. Hopefully, we still have enough time to get to the bottom of the remains in this new trench!

Jim Brightman with ITV film crew

The other excitement for the start of this week was the visit today by a team from our local ITV news programme. Word has spread quickly about the find of the William the Conqueror penny last week, and it was a lovely opportunity to spread the word a little wider still about the fantastic work that the volunteers have been doing through the course of the dig. For those who missed it (or are in a different ITV area), the full report can be found at this link:

https://www.itv.com/news/tyne-tees/2021-08-04/now-what-do-we-have-here-dig-uncovers-ancient-treasure-at-richmond-castle

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Richmond Castle Excavation Day 14: Another eventful week!

By Excavation Director Jim Brightman of Solstice Heritage

Reflecting at the end of the second week—two thirds of the way through our dig at the Castle—it’s been an amazing journey so far. After the excitement of the tv cameras on Thursday and Friday, we are all now taking a well-earned Sunday off, allowing some thinking time for the theories and interpretations. Yesterday, we were privileged to welcome a group from the Castle Studies Trust (one of the key project funders and hosts of this very blog!) who came to look round the excavations and offer some of their wonderful expertise and knowledge to help bring focus to some of the stories we are revealing.

Entreance/exit of a likely small postern gate at the at the exterior of the curtain wall immediately beneath trench 1 (courtesy of Dr Peter Purton)

Trench 1 has proven to be the most complex in terms of the intercutting layers and structures (what archaeologists call ‘stratigraphy’). Although there is plenty of time left for our thoughts to change with new evidence, we currently think we have an original narrow door at the base of the curtain wall which was blocked during the medieval period. After this, a small square stone building was constructed against the wall, again at some point during the Castle’s medieval life. In terms of the large stone piers and low stone wall that we can see above ground, however, we are now confident that they are indeed 20th-century inventions built by the Ministry of Works.

One of the most interesting aspects of Trench 1 has been the fantastic amount of fine medieval pottery that has come out of both the mixed topsoil and upper layers, and now from sealed medieval deposits. With a major acknowledgement to the eye and experience of Erik Matthews, we can confidently say we have not only great examples of local and regional pottery, but also of imported French and Belgian pottery. This really shows the importance of Richmond Castle as a seat of power during its medieval heyday and the interconnected nature of authority spanning the Channel in this period.

Range of pottery found in trench 1 (courtesy of Dr Peter Purton)

With the end of the project in sight, over the coming week I’ll also wrap up the stories for Trenches 2 and 3, so do keep checking back!

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Feature image courtesy of Dr Peter Purton.

Medieval Climate Change at Caerlaverock – Fieldwork Week Two

Project lead, Dr Richard Tipping, looks back at the second week of fieldwork he and Dr Eileen Tisdall are undertaking to try establish whether climate change did impact the re-positioning of Caerlaverock Castle.

Home again – after one of the most torrid week’s fieldwork I can recall: whilst Northern Ireland had the extreme weather warnings just to the east, Dumfries had day-time temperatures exceeding 26⁰C all week. And you’ll recall that I was inside a wood, where breezes never penetrate.

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At Caerlaverock on the Solway coast, we are trying to work out the natural and human impact of huge medieval storm surges on the 13th century old castle. Last time I was looking at how the moat, and possibly the castle itself, was inundated with seawater and mud driven shoreward by storms. This week I focused on the coastline itself, away from the castle. Before the storms hit, the old castle was on the coast: it had a harbour. You can still walk along the degraded cliff to the west of the castle and imagine the seascape. After the storms, the coast lay some 250 metres south of the castle. A series of large gravel ridges, tens of metres wide, grew southward, beautifully revealed in LiDAR images that peel away the nearly impenetrable woodland.

A visualisation from the LiDAR data showing the gravel ridges that Richard has been investigating this week

Each of these ridges created shallow basins protected from tides. The harbour became pointless as a result. But all we knew from earlier work was that the youngest basin was formed around AD1400. How old were the earlier ones? Could we find sediment dateable by radiocarbon?

The fieldwork, I knew, would be hard. I’d looked for dateable sediment before, simply by coring the sediments in the basins, and found only one site; and now there was the woodland to contend with. All you can do is remain patient and optimistic: unglamorous, muddy and unspectacular work. The woodland meant that some basins couldn’t now be found, others where I couldn’t core systematically, and still others where systematic coring failed to find anything to excite. But I think we can date three of the eight basins and, usefully, these include the earliest basin and the basin that blocked the harbour. Stay tuned.

An image from the LiDAR data of the old castle and its landscape. The moat and outer ditches I and II have been the subject of Richard’s investigations over the two weeks.

But it was the ditches around the old castle that were the highlight of a difficult week. Sense was made of the moat. The builders formed one of the four moat sides from an existing stream channel: the moat here is a lot deeper because of this. But then the castle mound was not made parallel with this moat side. It does seem to be a very slap-dash construction. The attempted buttressing of the castle by stonework in the moat is shown here.

And we can now show that the mud of the storm surges penetrated beyond the castle, not by a great distance but enough that the old castle would have been surrounded in these extreme events, laid siege by nature while the younger new castle was laid siege by Edward I and the English in AD1300.

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Feature image courtesy of Historic Environment Scotland

Richmond Castle Excavation Day 8: Mysteries on mysteries

By Excavation Director Jim Brightman of Solstice Archaeology

So, we are very much at that point on the dig where we are in amongst the really fascinating medieval archaeology, but we are still teasing the answers out of what are turning into quite complex layers.

One place where we are still not sure about whether we are seeing medieval archaeology is in Trench 1: ironically the one trench sited right against the colossal curtain wall of the Castle! The small finds have been outstanding from the upper levels, including a selection of particularly well made and decorated medieval pottery—evidence of the high-status dining that would have graced the tables of the great and good. As we have investigated the substantial buttresses, however, it is becoming increasingly clear that a lot of the stonework around the trench may in fact be an invention of the Ministry of Works in the 20th century! It turns out that the enterprising work teams may have gone a little beyond their remit of consolidation and let their imaginations run free!

Trench 3 is the biggest mystery of all though. We have a clear sequence back through time: modern topsoil, early-20th-century building foundations, the Victorian and later parade ground and a post-medieval soil that had built up after the Castle had fallen out of use. Beneath this, we were hoping for the remains of a medieval building, and that is what we have found. Sort of.

Trench 3 flagstones

The exposed remains comprise a series of massive limestone slabs, not squared and dressed like flagstones but nevertheless laid with some skill. They look a little like a yard that we might see in front of a typical Yorkshire Dales farm, but there are a set of slabs laid at an angle as if forming the side of a shallow pond. If this wasn’t strange enough, the whole arrangement is curved in an arc, part of a much larger feature extending beyond the trench. So far, all our theories don’t quite fit with what we can see in the trench, so the only thing left to do is dig more—out and down—and see what is revealed!

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Richmond Castle Excavations Day 4: Big digging and big rewards!

By Dig Director Jim Brightman of Solstice Archaeology

A quick update today as the main theme has been deploying mattocks to really push on through the more modern levels to try and reach the undisturbed medieval deposits. That means the main excitement of the day was the small finds that continue to emerge from the mixed overburden and 20th-century landscaping: animal bone in considerable quantities, more medieval pottery, what appears to be a hobnail and something that looks suspiciously like window lead.

The highlight of the day, however, was uncovered in Trench 3 (see plan below)—an area where we the volunteers are diligently digging through the clay dump of the former military parade ground in baking heat! What at first we thought was a corroded button (we’ve had one of those already), turned out on closer inspection to be a 14th-century French jetton!

Jettons were one example of a growing system of trade tokens often used in lieu of coins in specific areas or for specific trades. Jettons, however, were primarily used as accounting tokens, providing a visual means of making calculations on a large wooden board. This find gives us a fascinating insight into both the mechanics of medieval trade centred on Richmond Castle, and also the way in which many great magnates held considerable land on both sides of the Channel in this period.

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Richmond Castle Excavations Day 3: Horses and Walls

By Dig Director, Jim Brightman of Solstice Archaeology

Things are moving apace despite the sweltering conditions this week. We are now three days into the excavation, and all three trenches currently open have yielded up a variety of medieval pottery sherds as well as plenty of more recent artefacts.

Given the anticipated depths of some of the remains we are looking for, the last two days have seen a concerted flurry of digging to get through the topsoil and 20th-century overburden, particularly in Trenches 2 and 3. Once again the volunteers have excelled themselves and maintained a wonderfully positive attitude—whether debating the merits of marmalade and boiled egg toasties (apparently it’s a thing) or trying to convince the trench supervisors that they’ve found a Roman road (it wasn’t, but a good effort nevertheless).

Jaw of Horse

Perhaps the most excitement that was generated among visitors to the Castle, however, was the discovery of a largely complete jawbone from a horse! Although it was a little too high in the deposits to be evidence for medieval stables (or a meal!), it was a real reminder to everyone that as we’re digging ever deeper, we never truly know what we are going to find.

From the point of view of our main aims for the excavation, the biggest news of the day is that we starting to see the hints of probably medieval walling in both Trenches 1 and 2. Trench 1 by Robin Hood Tower is butted against the standing walls of the castle, but a lot of the stonework in this area was rebuilt and consolidated by the Ministry of Works in the 20th century. What we are seeing here are the first signs of original medieval stones beneath the surface—very exciting!

Possible remains of a medieval wall

Trench 2, however, was targeted to find part of a range of buildings never before known and revealed through geophysical survey. As the sun started to dip at the end of the day, and as we were starting to think about packing up the tools, loose rock started to turn up through the centre of the trench. A little more careful trowelling by the team soon revealed what may be the rubble core of a wall—our first window back into this untouched medieval structure.

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Revealing Richmond Castle’s Secrets: Excavation Starting Monday 19 July

Jim Brightman of Solstice Archaeology, dig director of the Richmond Castle excavation, outlines what the next three weeks of excavations of Richmond Castle to mark the 950th anniversary of its founding. The excavation is being co-funded by the Castle Studies Trust along with Richmond and District Civic Society and Richmond District Council.

By way of an introduction to the Richmond 950 community excavation, I’m going to start with a bit of a personal reminiscence. I am a former pupil at Richmond School, and in the dim and distant past when I was in in Lower School (the old Grammar School building), the first topic covered in history lessons was the medieval period. I’d already been fascinated by the past through primary school, and I was ready for it to be my favourite class. I wasn’t disappointed. On a seasonably warm autumn afternoon, we all trooped up the hill for our first site visit: Richmond Castle.

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Many, many years later, having studied archaeology at university and spent my early career in and around the Peak District, I moved back home in 2012. The first time I walked back into town, I vividly remember thinking “was the Castle always that big?!”. Then as now, and as in the centuries preceding, the keep towers over the marketplace, easily the most prominent building in the town’s skyline. Indeed, I was so taken with this icon of my childhood love of history, that the outline of the Castle now features on my company’s stationery!

Richmond Castle’s Great from the Bailey near where some of the trenches will be placed. Picture courtesy of English Heritage.

With the 950th anniversary of the Castle’s original founding rapidly approaching, I was overjoyed at the opportunity to run a volunteer archaeology excavation as part of the wider celebrations being held in the town through the course of 2021. Having been fortunate enough to be involved in a lot of community archaeology projects through the course of my career, it felt like a real homecoming.

As we started developing the project, it became clear that there was a wealth of places within the Castle where targeted excavation had the potential to shed light on parts of its story that have remained hidden. Geophysical survey in recent years has revealed whole complexes of possible walls and structures beneath the grassy sward of the bailey, and Richmond 950 is the first time that they will see the light of day for many, many centuries.

Richmond Castle from the air. Most of the excavation will take place along the far wall where many remains have been located. Picture courtesy of English Heritage.

The volunteer archaeology project was made a reality by the kind support of several funders, all of whom believed in the vision of engaging local people directly with the tangible past in such a beautiful and historic setting. We are very grateful to the Castle Studies Trust, Richmond and District Civic Society and Richmondshire District Council for their huge generosity and support – I feel strongly we will repay your trust with a fantastic project!

As I write this on the eve of the project starting, we are almost fully booked in terms of volunteer places—a real testament to the interest in archaeology in and around Richmond. That said, if you are reading this and getting the itch to try your hand at archaeology, then there are still a few places available on our Eventbrite link; no experience is required and everything you need to unlock your inner Indiana Jones is provided! Even if you are just interested in finding out more, then the Castle is still open to visitors through the next three weeks while we are digging, and we would be delighted to talk you through the unfolding story of the archaeology.

See you in the Castle!

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