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Post-Excavation

Well, nearly. Only slightly later than promised, I’ve managed to write the second part of the summary of our recent dating project. As well as re-dating the New Laund Enclosure to the Middle Iron Age, these results have also helped us pin down dates for some of the archaeology around the Whitewell Enclosure.

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We have one date from the top of the outer ditch, here in trench Q. This is on charcoal from an oak twig at the very top of the secondary fill of the ditch and it calibrates to between 1530 and 1425 BC. This ought to mean that the outer ditch, which of course is now completely buried, was still a visible feature in the landscape in the Middle Bronze Age.

This helps to make sense of one of the important questions about this site. Here we have a complex of lots of pits inside the three concentric ditches of the enclosure. Many of the finds from the pits and the enclosure look very similar but we don’t know if the pits and ditches were in use at the same time, whether some of the pits are earlier than the enclosure ditches or whether the enclosure came first and the pits were a later response to the visible remains of an earlier enclosure (confused yet, I know I am).

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This is pit M13, inside the enclosure, which we dug in 2014. A date on a fragment of alder charcoal from the top fill of this pit (just about behind Connie’s head) shows that it was in use in the Middle Bronze Age too, between 1500 and 1405 BC. M13 looks to be a long lived pit with many layers and both this date and the enclosure date are from the end of the sequence. All we can really say here is these things were still visible dents in the ground in the Middle Bronze Age.

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Pit N06 should have been the last in the complex of pits we excavated in 2014 in trench N. There are two dates from this pit fill, which cover the whole of the Early Bronze Age. One calibrates to between 2270 and 2030 BC and the later one to between 1745 and 1620 BC.

All of this tends to suggest that the pits and the Whitewell enclosure both begin before the Middle Bronze Age and have a long sequence. This makes it much more likely that, unlike what appears to have happened at the New Laund Enclosure, the worked stone tools (which seem to be Neolithic and Bronze Age) go with the excavated features.

Thanks to Denise at Oxford Archaeology (North), who identified all the wood in the first place, Oxford Radiocarbon Accelerator Unit and Beta Analytic Inc, who did the actual dating, and the Natural Environment Research Council and University of Central Lancashire, who paid for it all.

Rick

 

Last time I posted about radiocarbon I reported on an unexpected Iron Age date from the New Laund enclosure. At the time I suggested that the charcoal we dated had been moved into an earlier layer and I fingered the earthworm Lumbricus terrestris as the probable culprit. I can now completely and unreservedly withdraw this accusation.

Just about two weeks ago we had another batch of radiocarbon results back. These were all on charcoal fragments that Denise identified from the excavations at the New Laund and Whitewell Enclosures. Now I’ve had chance to think about what these results mean it is clear that we need to radically reassess our ideas about the New Laund Enclosure.

We have being trying to do two things with radiocarbon at New Laund. First to get dates that were both earlier than the construction of the circle of posts in the middle of the enclosure and then others that were later than its demolition – giving us an idea of not only when it was built but how long it was in use for. We were also trying to get dates from the enclosure ditch, to confirm our suspicion that the circle of posts and the ditch were in use at the same time.

(Very) long term readers may just about be able to recall that early in the 2012 season, when we started to dig the New Laund Enclosure, we fleetingly considered the idea that the site might be Iron Age. Then we started to find large quantities of worked stone tools, showing that there had been lots of either Neolithic or Early Bronze Age activity on this bit of the hill, and came to the conclusion that the features we were digging were likely to be of that date too.

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One of our new dates comes from here, about half way up the fill of the New Laund Enclosure ditch, and it calibrates to somewhere between 390 and 205 BC, right in the middle of the Middle Iron Age.

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On the timber structure itself we have the date from the bottom of this posthole showing construction also started in the 4th or 3rd centuries BC.

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And now we have another one from this upper fill of the same feature with exactly the same calibrated date range: 395  to 350 or 305  to 210 BC. This is excellent,as it allows us to combine the archaeological information with the radiocarbon dates. One radiocarbon date on its own tells you that there is a 94.5% chance that the thing you are dating died between a given range of dates. So the date from the base of the posthole only really told us that the structure was built at some point after 395 BC. Now we have this second date, which should have gone into the ground after the posts were removed, we can now be much more confident that the building, use and demolition of the structure all falls into the period between 395 and 210 BC.

What is round, later prehistoric and made of wood? Now we have an Iron Age date for this structure then the temptation to take our former timber circle, imagine a big round thatched roof on it and call it a roundhouse is very strong. If it is an Iron Age roundhouse it is a very big one. And, of course, the date from the main ditch suggests that it has a big enclosure around it. I am off to look up possible local parallels, which should make a whole blog post all on their own. There is also the question of what was going on at the site in the Late Neolithic or Early Bronze Age to leave all the worked stone artefacts we have found. However, next week’s post, assuming I get all the dissertations marked before then, will be an update on the new results from the Whitewell Enclosure, where the finds and the radiocarbon dates are in much closer agreement.

Rick

As it has been a little while* since my last post I thought I had better try and sum up all the progress we have had with the various projects since I last posted. This will chiefly involve telling you about what other people have been up to. I have been supervising five dissertations based on work we’ve done. These are all due in during the next month, so they are doubtless evolving and changing all the time, but I thought I would try and give you a flavour of what each student is up to and how it feeds into our overall research.

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Phil is looking at the prehistoric pits in and around the Whitewell Enclosure for his BSc project. He is interested in how the objects we found in each layer got to be there and what the differences were between the different shapes of pit. Inspired by work on big Neolithic pit complexes in East Anglia, he has been spreading all the finds from each layer in each pit out on tables in the archaeology lab to look for similarities and differences. This should hopefully let us see which pits are roughly the same date and were used in comparable ways.

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James is using all the magnetometer surveys carried out at New Laund since 2011 to look at what effect a whole lot of different factors have on the effectiveness of this kind of survey. Apart from involving him and Scott spending a lot of last summer walking up and down the farm, he has been pulling together information about the geology, topography and excavated archaeology. The plan is to be able to use this detailed information to give a really precise interpretation of all of the surveys.

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Dan is still working on the environmental evidence for his masters dissertation. Alongside the core he and Mairead took last summer he has been analysing a second core from further up the Hodder valley. We think that both the peat bogs sampled built up over the last 6000 years so together they should give a good picture of how the local environment changed during the period that the sites we have been digging were in use.

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Josh has been analysing the human and animal remains we excavated from Dunald Mill Hole in October last year for his BSc dissertation. He has discovered that the human bone from this site all seems to come from the same Romano-British child as the front of the skull first discovered by Di. Most of the bone is from the skull, although Josh has found a fragment of arm-bone too. He is sure that the original burial site was either at the entrance or even some way outside the cave and that all the bone was washed into the back of Pearl Passage, where we found it.

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Chelsea is re-analysing the human remains from George Rock Shelter, which Stephen and I excavated between 2005 and 2007. The bone and teeth from this site were originally studied by former students Gemma and Genvieve shortly after the dig finished. However, that was before we got radiocarbon evidence to show that although some of this bone is Neolithic there was also a much more recent burial at the site. For her BSc dissertation Chelsea has been trying to find a way to distinguish the ancient and (relatively) modern within the mass of mixed up fragments of bone.

*or if we are being strictly honest absolutely ages, apart from reblogging Julia’s lovely appreciation of Stephen, I now see that I haven’t posted anything here since October last year

I was out at Thornton earlier in the week to talk to the Wyre Archaeology Group about the discoveries we have made on the project and coincidently we have just had the first unofficial results from the radiocarbon dating programme. At the moment the dates don’t have lab numbers but they were all carried out by the Oxford Radiocarbon Accelerator Lab and funded by the Natural Environment Research Council’s NRCF scheme and we are very grateful for their support. As mentioned in previous posts we submitted bits of charcoal and bone from various features to try to build up a history of when the site was in use.

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This is [N06] the first feature that we have good dates for, the latest of a complex of intercutting pits inside the Whitewell enclosure and seen here being excavated by Phil and Kayla in July 2014. There were two layers in this pit and we managed to get a date from both of them. The lower fill built up sometime between 2271 and 2033 BC and charcoal was still going into the upper fill around 300 years later, as we have a date from that layer of between 1746 and 1618 BC. These dates belong at the beginning and end of the Early Bronze Age in Britain. We have always thought that [N06] was later than most of the other archaeology in this area, because the fill of it was visible as a charcoal spread from much higher in the sequence than some of the other pits. I think that this date shows that the complex as a whole was in use for a very long time, as we have a single late pit apparently in use for most of the Early Bronze Age. If the Whitewell Enclosure is a causewayed enclosure it should date to around 3600 BC, the use of the pits on the same hill clearly lasted for much longer than that. This is excellent news for our major project aim of trying to understand long-term landscape use and how people remembered special places.

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We also had some samples in from the presumed Late Neolithic henge and timber circle on the next spur of New Laund Hill. These included the single surviving piece of animal bone from that site (juvenile pig jaw) that Christina excavated with great care from the very sticky clay at the base of the henge ditch in 2012. This ought to have given us a very good date for when that ditch was originally dug but sadly, there was not enough collagen surviving in the bone to get a reliable result.

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We had two samples from this post-hole in the timber circle. One was a chunk of the cremation that was placed there after the post was put up and we are still waiting for that result to come back. The other was a small piece of hazel charcoal from base of the post-hole, which ought to tell us when the post was first erected. This date was entirely unexpected, given that timber circles are supposed to be either Late Neolithic or Early Bronze Age. That piece of hazel was burnt sometime in the Middle Iron Age, between 396 and 209 BC.

There are two possible explanations for this. Either we have found a very large round-house on the top of a hill, which is just coincidently full of earlier prehistoric types of worked chert, or, and I think I favour this explanation, the hazel charcoal has been accidentally displaced downwards into a much lower level than it was in originally. We did find some crucible fragments and charcoal in this general area at a much higher level which could well be Iron Age. If this is the case then my prime suspect for this is the earthworm Lumbricus terrestris. Thanks to many conversations with Kevin and Chris, UCLan’s resident earthworm specialists, I have seen impressive evidence of the depth that these animals can burrow. A single worm digs a vertical burrow with chambers which can be more than a metre deep.

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The (potentially) guilty party. The date we still have pending on the cremated bone from the top of the post-hole will be interesting. If that is Late Neolithic or Early Bronze Age, which is more in line with our expectations, then we will assume the hazel charcoal was intrusive. If that is Iron Age too then the worms are off the hook (sorry) and we have to come up with a new interpretation for our timber circle.

Rick

…where it touches. This week I have trying to push on with writing up the work we did at Moseley Height, outside Burnley. I’ve blogged before about this site. It was an Early Bronze Age ring cairn which was salvaged in advance of NCB open cast mining in 1950 by Walter Bennett of the Burnley Historical Society. We went back in 2010 to see what survived on the site. Thanks to the generosity of Mike at the Towneley Hall Museum in Burnley we’ve also got access to the orignal finds and records from the 1950 excavations. This is where the urn with the possible human bone tempering came from that I blogged about in January.

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This is what we found. We stripped a 20 by 30 m area in roughly the right place down to the level of the subsoil. This showed us the edge of the NCB’s open cast pit (the area of pale subsoil visible along the front edge of the trench) and also a lot of battered looking stones in more or less the place we were expecting to find the ring cairn.

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We focused our detailed digging in the area around the cairn. The dotted lines are contours at 0.1 m intervals and you can also see lots of surviving stone and rubble from the cairn. Feature [6], the very shallow base of either a pit or a stonehole, was the only archaeological feature that survived.

So, it was there, but it is now gone. The contours still show a vague circular shape in plan, with a dent in the middle where Bennett’s main trench was, but very little of the actual monument survives. However, what we did find was a lot of very nice worked stone, both chert and flint.

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This is a barbed and tanged arrowhead that Magda found on the last real day of digging. Nice to look at but also nice because these are very securely dated to the Early Bronze Age; it belongs with the ring cairn. There were also a lot of Early Bronze Age scrapers and flakes. Ross, who studied all this worked stone for his BSc dissertation, found out some surprising things about some of the other worked stone.

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These are bladelets (small blades) and two microliths, all of which ought to be about 3000 years older than the ring cairn. There was obviously a much longer history to this site than the Early Bronze Age burials. Long term activity at sites always fires the synapse in my brain that is marked ‘archaeology of memory’ (see what a good grasp I have of neuroscience). This in turn led me to thinking what else was there from Moseley Height that was earlier than the Early Bronze Age.

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When we looked at the collections in Towneley Hall then I found things like this. These two are either oblique or hollow-based arrowheads, either way they are Late Neolithic. This is actually much better evidence for meaningful group memory, they are likely to be generations older than the ring cairn, rather than millennia. We can realistically imagine that the people who built the ring cairn had some broadly accurate traditions about who the people who left these arrowheads were.

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Even more usefully, Bennett left a field drawing in the archive which shows where all his small finds came from. This is my digitized version of that plan. What is particularly interesting is that all the datable finds from the cluster to the north-west of the central pit are Late Neolithic, so this may mark the position of an early deposit right at the beginning of the use of the cairn. Sam, in her dating programme for human bone from Early Bronze Age sites, found that the first burial at Hindlow Cairn in Derbyshire was a Late Neolithic cremation.

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Of course, we’ve also got details of where all our finds cames from, although I am not so far on yet with splitting these up by date. What we really need to do is fit the two distributions together. This is a hard job because the only real points of contact between are two sets of records are 1) we know which way north is 2) the feature we dug as pit [6] is presumably a stonehole or pit base. Given where it is, it ought to be one of the stones on the north-west side of the outer cairn. This allows us to overlay the 1950 plan onto ours with a margin of error of about 2 metres, depending on which precise stone we think went in pit [6].

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This is my current best guess as to where the ring cairn used to be. Now I have got all these lovely pictures, I really need to get on and write some words to go with them.

Rick

Twice a year we have an oppotunity to bid for Natural Environment Research Council money to pay the Oxford University Radiocarbon Lab to do radiocarbon dates. Once of these deadlines was this Tuesday, so I have been on the scrounge for money again. You need a mass spectrometer to carry out radiocarbon dates so it’s not the sort of thing you can do in any old chemistry lab. If we had to pay for them individually each date would cost about £350, so you can see why this programme is a big help for archaeological research projects like ours. A couple of years ago I was part of a succesful bid with Sam, who was then a PhD student here, to get dates on a whole series of Early Bronze Age barrows from northern Britain. Sam has lots of details about the results here on her blog but we are also working on a joint paper about them (well, to be more strictly honest, Sam has done a lot of work and now the paper has landed in my in-box for me to get on with my bit next week).

Obviously NERC are not keen to chuck their money around dating things that they don’t think are important. I’ve posted previously about how we need to establish that we are dating viable samples but we also have to sell the project as a whole. Why is it important that we date these enclosures and how will this advance our knowledge of prehistory generally?

Denise, who identified all the charcoals for us, worked really hard to get a full list of the suitable samples ready for the deadline. What this also tells us, of course, is a lot more useful stuff about the finds distributions. Instead of a load of black blobs for ‘charcoal’ were are now in a position to look at what species of tree was being burnt where on site.

NL13 Trench D and H timber circle charcoal ids

This plan shows the identified charcoal from the timber circle we dug in 2012 and 2013. The dense concentration of charcoal around the entrance we always thought was connected with the cremation burial from the same place. Now we can see that the pyre fuel seems to have been predominantly alder and/or hazel. Most of the larger, slower growing trees like oak and ash come from different parts of the site.

This also helps confirm what we thought from the archaeology that, unlike some other timber circles, none of the big posts here were burnt down. If they had been we would have expected to see a lot more oak charcoal.

The charcoal finds from all the sites Denise has looked at so far has had a lot of hazel and alder in it. Although this is not as systematic as we hope the results from the wet sieved samples will be, it does give us a suggestion that in the Neolithic this was a landscape that was mostly small trees and bushes, rather than large forest species.

Rick

It was all words and no pictures last week. This week I have been generating many finds distribution plots to even things up. These are based on the results of some work that Dan has been doing on last summer’s finds. He has been going through them and tidying up the spreadsheets. Partly this is about consistency – making sure that a piece of flint we classed a flake one day is similar to other pieces of flint classed in the same way a week later.

N20 finds by type

Even at this level we can get a lot out of this. This is all the stone tool finds from trench N sorted by type. Apart from giving a great sense of how much stuff there was in this pit complex, the other interesting thing is the way that all the blades (longer, thinner and more regular flakes) seem to cluster on the south-east side of the pit.

N20 finds by material

Looking at what everything was made of in trench N, we can see that the charcoal and burnt bone were mostly associated with the smaller, deeper pits up to the north. This plot is even busier than the last one as it includes all the other finds as well as the worked stone. In fact there was even more stuff in these pits because these plots don’t include quite a lot of things we found while sieving which don’t have such precise co-ordinates.

M finds by material

For comparison we have done the same kind of plot for trench M. One thing this seems to show is that the pit with former postholes in it [M13] has more variety of finds in it than the rest of the features in this bit of the site.

M finds by type

Although if we look at the type of stones tools and where we found them in trench M then the picture is more varied, with cores, scrapers, flakes and blades coming from all different parts of the trench. The features in both trench M and trench N should be Neolithic pits inside the probable causewayed enclosure we found last year.

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We are still working on looking at what we found where in the outer ditch of the enclosure. This is a screen grab of the basic distribution pot in QGIS for the eastern part of the outer ditch as we excavated it in trench P. It shows the stone tools divided into flakes and blades for this area. Even though I haven’t got a nicely digitized plan to overlay this on yet you can clearly see the line of the ditch just by the increase in the density of finds.

Rick