A lost long barrow rediscovered?

In a previous post, I described an initial survey which aimed to look for a lost long barrow near Sopley.  The barrow was apparently bulldozed by American troops in WW2 to make way for Winkton airfield.  The first survey took in two 20m squares, and although inconclusive, gave a tantalising hint that there may be a large feature which potentially continued outside the survey area.

Yesterday, members of AVAS and The Christchurch Antiquarians returned to the site to extend the survey area.  Conditions were challenging, with numerous trees and bushes to navigate around.  However, the results were amazing, as shown below

The image above shows a large high resistance feature, shown in white and light grey, which appears to have a curved end to the south.  This feature is about 65m in length.  The shape of this feature suggests it is man made Continue reading

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Searching for a lost long barrow

On a web page recording memories of Winkton airfield, near Sopley, there is the following reference to the blatant destruction of a barrow to support the war effort:

“Apparently the site of the airfield contained an old burial mound, a barrow, claimed to be the site of the burial of warriors killed in a local battle between the Danes and King Alfred’s forces. The barrow was flattened during the preparation work for the aerodrome and Canon Kirkham expressed some concern at this to the commanding officer of the unit concerned. The officer was apologetic and offered to put it back again !!!”

At that time it was popular to attribute such barrows to the Danes or Saxons, but it is more likely that this barrow was Neolithic in date.  Sue Newman has uncovered further documentary evidence, including the following extract from the Gentleman’s Magazine 1861 describing activities of the Christchurch Archaeological Society:

“A barrow of seventy yards in length, and twenty yards in breadth, in the neighbourhood of Dane-rout, or Danat Lane, in the Clock-field on his property, will be opened by him in the course of the spring.”

The old OS maps of the area show an interesting long thin enclosure, of similar dimensions, in a wooded area called Clockhouse Copse.  This copse was truncated on two sides when Winkton airfield was built, and the area of the enclosure is in the part of the copse that was destroyed.  This can be seen in the maps below.

The trig point within the enclosure is also of interest, as these were usually located on raised ground.  Sue Newman has also discovered that on the tithe map for the area, the field surrounding this enclosure was called ‘Burrow Close’, possibly a derivation of ‘Barrow Close’.

Given this evidence, AVAS recently undertook a joint survey with The Christchurch Antiquarians to Continue reading

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Hampshire Field Club Proceedings available online

Hampshire Field Club and Archaeological Society have recently made their proceedings available online.  Volumes from 1920 to 2014 are available as PDFs, with links available on the main Hampshire Studies web page.

Some highlights include:

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Gradiometer survey of second mound

We were extremely fortunate with the weather yesterday whilst carrying out further survey work on the second possible long barrow (see Promising results from second gradiometer survey).  Progress was slow due to barbed wire fences and hedges crossing the survey area, as well as very rough ground.  Partial squares tested our ability to add dummy readings and dummy lines, but all worked out fine.

We have gradually added more small areas to the survey of this mound, and the picture is beginning to become much clearer, as shown below:

Gradiometer results for second mound

Gradiometer results for second mound

The width of the survey data is 80m.  There is a wide feature that flanks the mound, and which looks like a northerly ditch.  Things are less clear to the south.  A barbed wire fence crosses horizontally across the centre of the plot.

After finishing that survey, we thought we would try to locate a small ring ditch in the adjacent field, recorded as having an unusual shape.  With an imprecise coordinate, and an imprecise GPS position from my phone, we missed the feature completely in our first 20m square, but were successful second time around:

Small ring ditch

Small ring ditch

It isn’t that remarkable, although appears to have a gap to the west.

Today I returned the gradiometer to the New Forest National Park offices in Lymington, which draws to a close our survey work for now.  I thought it was worth including the surveys of our other sites in the fields adjacent to those above, as we are very pleased with the results.

Here is the survey from the first mound, which has all the indications of a classic long barrow.  The width of the plot is 80m.

Long barrow 1

Long barrow 1

Here are the results from the double ring ditch:

Double ring ditch

Double ring ditch

I have uploaded some photos to the AVAS Flickr site, here is one example:

AVAS Geophysics 13 Nov 2016

Thanks to everyone in AVAS for helping out with the surveys, to Bournemouth University for the load of the equipment, and to the New Forest National Park Authority for arranging the loan of the equipment.

 

 

 

 

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Promising results from second gradiometer survey

Last week we undertook our second gradiometer survey using the gradiometer loaned out by Bournemouth University as part of the LoCATE project.  The survey site was a second ploughed out mound about 200m north of the site of our first survey.  The first survey had indicated rather conclusively the site of a long barrow;  a second long barrow in close proximity would be a significant and unusual find.

This survey was much more difficult than our first.  We had just calibrated the meter when thunder rumbled and there was a heavy downpour.  We also had to contend with a barbed wire fence cutting the site in half, as well as partial grid squares caused by field boundaries, hedges and thick vegetation.  We had to work quickly given the looming black clouds.

Given these difficulties, we are very happy with the initial results, as shown below (plot dimensions are 60m x 40m, north to top):

Gradiometer - second mound

Initial results for mound 2

We were only able to survey the eastern part of the mound.  It is possible to discern a clear, regular anomaly which curves around to the east and then travels in straight lines westwards at the top and bottom.  These lines appear to be starting to converge, suggesting a tapering anomaly which reflects the general shape of the mound.  The strong black and white horizontal disturbance across the middle of the plot represents the barbed wire fence, and there is a very strong white anomaly in the top part of the plot which we are currently puzzled by.  The red parts of the plot represent areas we did not survey.  The wide dark anomaly above the curving anomaly could represent the terminal of a wide ditch;  we will need to extend the survey area to the north to investigate this further.

In conclusion, these results are less conclusive than those for our first survey.  However, the regular nature of the anomalies suggest that we are dealing with a man made rather than natural mound, and the general pattern is certainly conducive to an interpretation of a second long barrow.  How exciting if we can prove this!  We now plan to extend the survey area where possible to investigate further this theory.  We will also consult with the resident experts at Bournemouth University for their opinion on the results.

Thanks to :

  • everyone who helped with the survey
  • Bournemouth University for loaning out their equipment
  • the New Forest National Park Authority for coordinating the loan of the equipment

 

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Lecture Series 2016-17

The first three lectures for the 2016-17 season have been announced on the AVAS website.  Follow this link to the Meetings page for details.  The talks represent an eclectic mix of subjects and geographical regions, from the Maya of Central America to Stoney Cross Airfield a little closer to home.  Also, Professor Tony King will be talking about a fascinating Roman find at Meonstoke.

We will be announcing more talks shortly.  Visitors are very welcome.

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Successful first gradiometer survey

Last weekend a group of AVAS members undertook their first gradiometer survey using equipment borrowed from Bournemouth University.  The equipment is being lent out to local archaeological groups as part of a project called LoCATE (Local Community Archaeological Training and Equipment), which is a partnership between the Archaeology Department at Bournemouth University and the New Forest National Park Authority.

The site was between Salisbury and Ringwood in the Avon Valley.  The field in question contains a distinct ploughed out mound about 60m long in a field now used for pasture.  We did a resistivity survey here in 2011, which picked out the shape of a regular long mound, but failed to locate any possible ditches;  the jury was out on whether this was a long barrow.

IMG_4459

After locating the fence posts used as survey points for our 2011 resistivity survey, we soon had our grid squares set out.  It took a little while to calibrate the gradiometer, but we were quickly able to complete a couple of squares.  We took a break to download the results.  The bright sunshine meant it was difficult to see the laptop screen, but we could make out a couple of distinct lines which appeared to respect the mound.  It looked like we might be picking up two ditches.

IMG_4493

Mark and Jan undertaking the survey. This photo also shows the mound, which is hiding the car to the right.

We were able to rapidly survey another four squares, with a short break for lunch.  I had downloaded the results for the first four squares, and the results looked promising, but again it was hard to see on the laptop.

On trying to exit the field, our way was blocked by an angry herd of bulls, but Rachel was braver than me and jumped over the gate to encourage them out of the way.

IMG_4534

I rushed home in eager anticipation.  How clear would the results be for all six squares?  I was blown away by the results when they appeared on the computer screen, as shown below:

Gradiometer results

Gradiometer results

The plot shows two long wide anomalies that appear to be outer ditches.  However, what was totally unexpected, and hadn’t been clear when reviewing the results in the field, was the trapezoidal shape positioned between the ditches.  This is a classic long barrow shape, and clearly resembles the plan of the excavated long barrow of Fussell’s Lodge, near Salisbury:

Plan of Fussell's Lodge long barrow

Plan of Fussell’s Lodge long barrow

In the case of Fussell’s Lodge, the trapezoidal shape represented a bedding trench used to hold timbers which acted a s a revetment for the mound.

Our first venture out with the gradiometer had been a huge success.  We now need to extend our survey area to pick up the full shape of the outer ditches.  Many thanks to Bournemouth University for lending out their equipment, and to the New Forest NPA for hosting the equipment.  See our the AVAS Flickr feed for more photos.

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Environment Agency Lidar data shows archaeological potential

The announcement earlier this year that the Environment Agency was to make its Lidar data freely available was welcomed by archaeologists, who are able to use the detailed terrain height data to add a new dimension to existing aerial photographs, and provide a new source of data for studying archaeological features.  This is of particular importance to amateur archaeologists, who are unable to afford the cost of commercially acquired Lidar data.  The access to this data, in addition to the maturity of open source computer applications, means that such archaeologists can begin to make a real and effective contribution to the study of landscape features.

Whitsbury Iron Age Hillfort - 1m DTM Lidar

Whitsbury Iron Age Hillfort – 1m DTM Lidar

Lidar data can now be downloaded from the Environment data.gov.uk portal.  Simply click on the map;  a square will appear on the map and the available downloads will appear in a list below.  There are two types of Lidar data:

  • Digital Terrain Model (DTM) – the bare earth, with buildings and vegetation removed
  • Digital Surface Model (DSM) – the model includes buildings and vegetation

For archaeological purposes, the DTM is probably most useful, as trees and bushes are stripped away to reveal any earthworks below.  The downloaded zip includes a series text files with a .asc extension;  these are text files which contain an array of height values for a specific small tile.  Many Geographical Information System (GIS) software packages can read this data directly;  I used the open source and freely available QGIS package.

The most effective way of visualising Lidar data is with some sort of hillshade applied, which simulates the lighting of the landscape with sunlight from a particular direction and height.  The problem with shading from just one direction is that linear features aligned with the direction of shading will not create a shadow.  For archaeological applications, it is normal to create a composite of hillshades from a number of directions, using different colours to represent each hillshade.  I used the excellent and freely available Relief Visualization Toolbox to create these hillshade composites.  The picture above of Whitsbury Hillfort, near Fordingbridge in Hampshire, is an example of this type of rendering.  A vertical exaggeration can be used to strengthen the depiction of subtle features.

Once all of the hillshade images were created, I used a command line tool called GDAL to create a mosaic of all the images, called a VRT file.  GDAL tools are available from the menus within QGIS.  A screenshot is shown below [click on the image to enlarge].

Lidar composite in QGIS

Lidar composite in QGIS

It is worth noting that there is not a full national coverage of EA Lidar data;  most river valleys and surrounding areas are available.  The black areas in the screenshot above are locations where no data is available.

So what have I seen so far during an initial browse of the data in the general region of the Avon Valley?  I have picked out a few areas below.

Whitsbury Hillfort

The screenshot of Whitsbury hillfort above shows the potential for depicting existing earthworks which are normally shrouded in thick vegetation.  The detail shown in the ramparts can be compared to the original Royal Commission earthwork plan, and reveals subtle details not previously recognised.

Bokerley Dyke and the end of the Great Dorset Cursus

Lidar showing the end of the Great Dorset Cursus

Lidar showing the end of the Great Dorset Cursus

[Click on the image to enlarge].  This is perhaps my favourite area, showing a palimpsest of landscape features of true temporal depth.  The end of the Neolithic Cursus can be seen in the centre of the image as a large subtle rectangular feature, which heads off towards the south west corner of the image.  The much clearer long thin linear feature which points at the end of the cursus is a long barrow, as is the similar long barrow to the south.  The former long barrow has long been suspected of being two adjoined long barrows, and this is borne out by the Lidar, which shows two sections on slightly different alignments.  There is another ploughed out long barrow to the north of the cursus, which shows as an oval mound.

The large bank and ditch which snakes from north west to south east is Bokerley Dyke, a linear boundary which probably had significance in the Bronze Age and Iron Age, and was most likely strengthened in the late Roman period.  To the east of Bokerley Dyke, a series of probable Prehistoric field boundaries can be seen.  Finally, the substantial rectangular earthwork in the top centre of the image brings us into the 20th Century, representing an army training range.

Rockbourne Down

Field systems around Rockbourne Down

Field systems around Rockbourne Down

[Click on the image to enlarge].  This image shows an extensive field system on and around Rockbourne Down.  Most of the field boundaries are under plough, but the crisp boundaries to the east of the image are still under pasture and much better preserved.  There also happen to be three long barrows on this image.  The one at the centre top is the huge and well preserved ‘Round Clump’, with the mound and ditches clearly depicted in the Lidar data.  At the western side of the image is the ploughed out Rockbourne Down long barrow, pointing in a SSE direction.  To the east of the image, crossed by the horizontal blue grid line is a much smaller long barrow mound.

In summary, now that the Environment Agency Lidar data is now freely available, amateur archaeologists have at their disposal a rich new source of data to study past landscapes and discover new sites.  The images above show the potential for this resource, which can be used to illuminate even the most subtle earthworks with an unprecedented clarity.

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AVAS members enjoy lecture

At the AVAS lecture for October, AVAS members were treated to a fascinating talk from Dave Fawcett, and expert in historic arms and armour.  In the first part of the talk, Dave talked about the intricate jostling for power among members of the French and English royal families, and how this translated into a series of battles in the Hundred Years War, culminating in the famous Battle of Agincourt.  The second part of the talk concentrated on the arms and armour, and Dave had kindly brought along a number of replica examples which we we able to try out for real.  I have added a number of photos below, and should add that no AVAS members were harmed during playtime with the weapons.  More photos are available on the AVAS Flickr photostream.

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AVAS Lecture Series for 2015-16

The initial programme of talks in the AVAS 2015-16 lecture series has been announced on the meetings page on the main AVAS website.  Some talks later in the year are still to be confirmed, but the first few lectures look really interesting, spanning the Palaeolithic to the Hundred Years War.

Jane Ellis-Schön, Project Director of the Finding Pitt Rivers Project, will open the lecture series on 2nd September 2015.  She will  talk about cataloguing and researching the Pitt Rivers Wessex collection at Salisbury Museum.  The timing of this talk is particularly apposite given the start of the Foundations of Archaeology project, which celebrates the work of the pioneering archaeologists who first identified the rich upland archaeology of south Wiltshire and north east Dorset.  The latter project will be looking at two site excavated by Pitt Rivers:  Wor Barrow and Winklebury Hill.

Visitors are made very welcome at the AVAS lecture meetings, which are held in Ringwood on the first Wednesday of the month between September and May – see the meetings page on the main AVAS website for more details.

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