Archive

survey

We haven’t done any excavation on the project this summer but we have been working hard on making sense of everything we have found over the last five years. In particular, we have been trying to understand how the Middle Iron Age timber features and bank and ditch of the New Laund Enclosure fit together.

Gradiometer details 2011

Alex is working on this for his Masters dissertation. He is re-examining the existing geophysics, like this gradiometer plot of the features from 2011, looking at the ceramics and metalworking slag from the topsoil and re-evaluating the excavations from 2012 and 2013.

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However, he has also been doing some fieldwork. We now have a(nother) new toy. This is the Ground Penetrating Rader set in action on the enclosure interior last Friday. (obviously the only damp day of last week). It looks like a lawnmower† but inside the bit that looks as if it should be the grass-collecting box are three different frequency rader antennae. GPR works by detecting these radar waves as they bounce off any sub-surface features.

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This is the driver’s eye view, taken as I paused during one of my traverses. The tablet screen shows three vertical slices through the ground directly beneath the machine, one for each frequency of radar in use. We recorded 130 of these traverses on Friday, and therefore 390 scans in total, covering a 28 by 18 metre area just to the west of trench D from 2012 and trench H from 2013.

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This is only the third time we have used the GPR but I’ve already learnt that, laborious although the data collection feels while you are doing it, the real work will start next week when we download the data and begin the computer processing. The vertical slices you see on the screen as you are recording the data are extremely confusing to look at. They show the time the radar waves take to travel through the ground, rather than any scale measurement of what is beneath you. They also show multiple reflections from any target. To get anything which will be comparable to the existing ‘plan view’ geophysical results Alex is going to have to process all these effects and reflections out and then stack all the vertical traverses up together in their right geographical location next to each other.

Once this is done then it will be possible to virtually ‘slice’ through these at right angles and produce many plan views at different depths. Some of these will hopefully show the post-holes and foundation slots of the timber features. Of course the great strength of the GPR is that, unlike other geophysical techniques, you get this three dimensional view. Hopefully, not only will we be able to see if there are features in the area we surveyed but we should also be able to tell whether they are at the right depth to be part of the same structures as the features we dug in this area in 2012 and 2013.

Rick

†On Friday I kept thinking that actual lawnmower blades on the front of the antennae set would be a good after-market accessory. We had to push through some very stubborn tussocks of reeds to do the survey.

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Rob and I have been up on site today. We have been moving equipment and surveying before everyone else turns up to start digging on Monday. When we got to the farm this morning there was no-one around (as indeed there hasn’t been most of the week) but Daniel’s dog was standing in the beck looking very hot and slurping down gallons of water. After a bit, John and Daniel turned up on a quad. They have been gathering and shearing the sheep all week over at Dinkling Green, which is about three miles away. After a week of this in the heat and humidity the dog had decided that enough was enough and had taken herself off home for an unsanctioned holiday.

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After we had climbed up the hill in the airless humidity we could kind of see where she was coming from. This is the first time I can remember that it hasn’t been raining when we have come to lay out the site grid. As I have mentioned before, it is good to get these jobs done before everyone else is on site. Obviously, no one can start digging until we have correctly located the positions of the trenches on top of the geophysical anomalies we want to investigate. Equally obviously, a hot day and complex machinery means that there will be plenty of opportunity for doing things several times until you identify the simple mistake which means the total station keeps saying Bad Data Error – unable to compute position. These are the times when it is good not to have an audience of 20 people leaning on shovels waiting for you to get it right so that they can start work.

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Eventually we sorted it. The forest of wooden grid pegs in this photo marks the position of the trenches we are going to start digging on Monday. There is a 20 x 20 metre area where we have the innermost ditch of the causewayed enclosure particularly well-defined. We have marked this out with four pegs but unless we are feeling particularly superhuman we will not be digging the whole area. Within this space we have set up two 6 by 4 metre evaluations which is where we will start work. Once we have some results from those we will expand the excavated area as necessary. We just need to remember not to put anything large and immovable (like grab bags full of spoil for example) down anywhere within the 20 x 20 metre area. We will also need to fence a compound off with the electric fence from the beginning. As you can see we have both cattle and sheep in the field with us at the moment. We have even treated ourselves to a new energizer for the electric fence.

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Wildlife of the day has to be the scary mutant triffid/cactus/thistle thing I found growing further up the pasture. Suggestions as to what this is and how it happens from anyone with more botanical knowledge than me (so anyone with a pulse, basically) would be very welcome.

Rick

Scott and James have started work today on what should be about a week’s gradiometer survey in the landscapes around New Laund Hill. The plan is for them to survey large chunks of the different slopes and elevations. This is hopefully going to provide them both with MSci dissertation topics as they investigate the prehistoric landscape around the known archaeology we have been excavating for the last few years.

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They started down by the river, on the alluvial floodplain opposite the Inn at Whitewell. We’d chosen to do the survey this week because 1) all this year’s assessments are now finished (they are nearly all marked too) so we should all have a bit more time for research and 2) its bound to be sunny on the 1st of June isn’t it? This is the view down from New Laund farm towards the river plain, the small wet dots trudging backwards and forwards are James and Scott.

While they were doing the actual gradiometer work Clare and I were running around the farm ahead of them with the total station fixing the position of the survey onto the OS national grid. I’ve explained how the gradiometer works, to the best of my ability, before. As well as detecting the buried archaeology, we also need to be able to locate it on our maps of the area. The easiest way to do this is to make sure that the 30 x 30 m areas we survey have whole number national grid co-ordinates at the corners.

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The weather was actually less miserable than forecast yesterday. It stayed dry until about 1.00 and the gales and heavy rain that Scott is battling into here only turned up about 3.00. Clare and I had it relatively lucky. We didn’t need to be non-magnetic to do our part of the job and so could wear proper waterproofs and boots.

Survey continues tomorrow – yellow warning of wind say the Met Office – and Dan, Mairead and I will also be sampling for pollen further up the hill as part of Dan’s MSci dissertation. Wildlife of the day was curlews, they whizz about the lower meadows on the farm in stupendous numbers, which kept almost crashing into Clare and I as we worked.

Rick

Wednesday morning, to be precise. I set off on a trip into the uncharted territory otherwise known as the East Riding, to collect some flint samples. This wasn’t quite the epic trek it would have been from Preston because we were over in Scarborough for New Year.

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The samples are for Vicki and Matt’s PhD student Aine, who is using a range of different spectroscopic techniques to look at which trace elements are present in prehistoric flint tools. The idea is that the trace elements in different flint outcrops ought to vary enough to allow her to identify which flint sources were used to make the tools. She has already sampled a whole range of flint tools but she also needs samples from as wide a range of flint sources as possible. Hence my trip down into the East Riding, and specifically to the chalk cliffs around Flamborough Head.

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This is the sample site Aine had chosen, North Landing, just to the north of  Flamborough Head itself. It is a tiny north-east facing cove with what must be a delightful beach in the summer. At ten o clock on the last day of the year it was deserted except for a very few hardy dog walkers and me.

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Down at sea level it was exactly as cold as it looks in this photo. My job was to walk along the cliffs looking for outcropping flint, pick up as many loose bits as possible and link the samples to identified parts of the outcrop.

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As you can see in this photo there are bands of flint showing in the chalk at the base of the cliffs on the north side of the bay. These layers are very pale grey and opaque. They are quite chert-like in overall appearance and the bits I picked up didn’t look to be very good quality. I collected them anyway, although I am not confident that they would have made good stone tools.

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There were some much finer, black flint nodules lying around on the beach but it wasn’t until I looked in the debris from this recent cliff fall, also on the north side of the bay, that I spotted where this flint was coming from. I picked up lots of glassy black flint from within this pile of mud and chalk. There was clearly a band of the finer grade flint right up at the top of the chalk. I got lots of bits of both types of flint, hopefully Aine will be able to make sense of it all.

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I had a Frank Sutcliffe moment on the way back up the slipway, cobles in the morning light awaiting their turn at the shoals of herring.

Rick

More thinking through pictures this week. Next summer, provided John is happy for us to carry on digging up his pasture, then we are going to try to excavate some of the innner ditch segments and interior of the Whitewell Enclosure. In an attempt to still keep some kind of focus on the wider study area I’ve decided that it would also be good to do some targeted areas of gradiometer survey in the spring. There are two areas in particular that I want to look at. Trying to locate these surveys has brought me back to working on the landscape zones that I set up last spring.

Beer garden

To re-cap, these are supposed to be parts of the study area which have similar physical characteristics. If we sample an equal amount of each of these zones then we should be evenly covering the whole study area. This is the flat land enclosed by the bend in the Hodder opposite the Inn at Whitewell. As you can see from the screen grab I have also got on with the essential task of thinking up whimsical shipping forecast style names for these territories. This is Beer Garden because you can see it from the pub. I want to survey here because I think that there will be a thick layer of river silt over any prehistoric archaeology. This will make it harder to get at but should ensure that it is well-preserved.

Reed Barn

To the north-west of Beer Garden is Reed Barn (named after the farm smack bang in the middle of it). This is at a slightly higher elevation and isn’t as flat but there should still be lots of river silt here too. Mike did his master’s dissertation looking at how investigate precisely this kind of landscape in the Ribble Valley, so I’m hoping we can apply some of his methodologies here.

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To the west of the zones where we have already done lots of work there is another flat(tish) bit of land. This is the area which included Mouse Hole, one of the caves we dug in 2011, but the whole flat plateau behind is covered in dolines. Geophysics here might tell us quite a lot about how the cave systems work but also, hopefully, reveal other unknown archaeology. The other thing you can see in this image is how we have parcelled out the rest of New Laund Hill. By a process of contraction, the plateau that includes Fairy Holes, the Whitewell Enclosure and Temple Cave has become the Arthur Rackhamesque Fairy Temple. To the north of that is Television. This is not me coming over all New Wave. Apart from sheep there are two obvious features in this zone, one is a big lime quarry (and you find them all over the study area) and the other is the TV mast that means the farm has any terrestrial reception at all. Above that is Timber Circle, because there is one there. Beyond Timber Circle the hill falls off down to the valley floor. This zone is all steep and north-facing, hence North Face. This has left us with a long thin, east facing buffer state between the rest which I have imaginatively called New Laund.

Rick

The trouble with excavation is when you are doing it you are often so busy keeping on top of all the tasks that need to be done you forget to think about what it all means. This summer we had some fantastic results, lots of worked stone from the pits we were digging and a mass of geophysical data from the big survey that Mike and his team carried out. Now I have had half a day to do some basic analysis it is clear that, as we suspected a few weeks ago, we have found another important prehistoric ritual monument. (This is a project, remember, that is supposed to be about the use of natural spaces and landscapes).

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Here are the results of the gradiometer survey as they were plotted out in QGIS. This is the processed data from the survey but it has not otherwise been interpreted. Consequently we are looking at a mish-mash of archaeology, geology and spikes caused by iron objects in the topsoil (usually old horse-shoes and bits that have fallen off tractors). What I have been meaning to get around to doing since late July is to use the results of our digging to try to distinguish between the different kinds of response in this plot.

NL14 gradiometer interpretation screenshot

Ta Dah!

The red things in this image are responses that looked similar to the ones in trenches P and Q. Based on what we found in those two trenches these should be relatively shallow ditches. The blue spots are the ones that looked very similar to the pits in trenches M and N, and therefore it is likely that they are the remains of pits too.

As soon as I had done this, I got everyone into my office to look at the pretty pictures on my computer screen. Straight away, entirely unprompted by me, Vicki said ‘That’s a causewayed enclosure’. We then had a bit of a poke about on our bookshelves looking at possible comparisons.

Other causewayed enclosures

This image of known causewayed enclosures from southern England comes from Alasdair Oswald, Carolyn Dyer and Martin Barber’s book on the subject (which is on the reading list). With a bit of Photoshoppery I have added the outline of the new Whitewell enclosure on at the same scale.

If we are right then the Whitewell Enclsoure should be Early Neolithic. It probably dates to between 3700 and 3500 BC (there has recently been a massive AHRC funded project reanalysing the dates of just these kinds of monuments, published as the two volume book Gathering Time – also on the reading list). It is likely to be about 1000 years older than the henge and timber circle of the New Laund Enclosure that we were digging in 2012 and 2013.

Whether we have got the date right or not there is an important lesson here. In an area where not much previous research has been done then it is not safe to assume that no evidence equals no archaeology. Since we started digging in 2011 we have found two prehistoric enclosures within 500 m of each other. Next summer we need to go back and dig more of the interior of the Whitewell Enclosure and find out about those inner circuits of ditches and more of those pits.

Rick

Yesterday we got our magnetic powers back. Our gradiometer is still away being fixed but the replacement hire machine turned up on Monday. Mike, Scott and James have been using it to complete the survey of the pasture.

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Here is all the data, fifty seven 30 x 30 metre grids in total, after Mike and James processed it and I have located it onto the mapping in QGIS. This year’s trenches are marked in blue and you can see that the ditch we found in trench P (bottom left of the plot) continues around the hill. It then seems to curve up to the north, about level with survey point 24, before returning along the other side of the hill to where we put trench Q. Excitingly, there also seems to be another circular ditch inside the bigger one. This would just cover  the higher bit of the hill. Inside the ditches we can see many similar anomalies to the ones which we dug this year. These are all likely to be prehistoric pits too.

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We have even better evidence that the ditch continues around the hill from trench Q. Cut into the natural glacial clay here we have found a small v-shaped ditch with a silty upper fill. This is almost identical to the shape and fill of the rock cut ditch in trench P on the other side of the hill. Although it has quite a lot of charcoal in it, it doesn’t have anywhere near the density of worked stone we found in trench P. This may be because this part of the ditch is much further away from the big pit clusters, and hence the centre of the occupation area.

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The giant pit in trench N is a very good example of the kind of thing some of the other anomalies in the magnetic data probably represent. This one seems to have had quite a long period of use, with layers of filling visible. You can see the difference between a dark brown upper fill and a much lighter deposit at the base in the section behind Jack’s boots as he helps finish a final clean of this. I, meanwhile, was standing on the grab bags photo-directing to get the best possible shot of all these layers in their pit. I suspect this feature will finish up on the cover of this year’s interim report.

Mike saw two weasels playing on the way up the hill from the barn this afternoon. This was going to be wildlife of the day but is probably pipped by the trench Q selfie (if you call it a selfie when you take it on a Nikon D90 digital SLR).

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Apologies to Ravelry for stealing their pun for the title, and to James, whose job it normally is to make the puns on site.

Rick