Quite a few of Gamlingay’s older residents remember and have fond memories of a tithe barn which used to stand  on St Mary’s field, east of the village church. Sadly, the barn was destroyed by a fire in the 1960’s. Although some photographic evidence of it has come to light, and there is an unnamed building on an old OS map thought to represent the barn, its exact  location remains uncertain. So, what better way for our group to cut its archaeological teeth than to try to find precisely where the barn once stood? Here’s an overview of progress to date (August 2013). Through the winter of 2012 at our Gamarch meetings we gathered and reviewed the information we had to hand as regards the barn’s location. This consisted of a mix of anecdotal and photographic evidence, a single text reference and one map source. Not much to go on but it was a start. The text reference came from a Victoria County History volume :-  ” The sites of two medieval manor-houses, one moated, lie beyond the church at the east end of the triangular green, an area which also included a complex of buildings centred on the rectory house, in 1967 represented only by a tithe barn and the late-medieval house known as Emplins.” (see text and footnotes of this online article). Even though this mentions the barn it doesn’t narrow down the site of the tithe barn more closely than could our anecdotal and photographic evidence and so we simply made note of what the text said and moved on.

The common strands or recurring themes within the anecdotal evidence were that the tithe barn stood in St. Mary’s field, lay close to one of the paths across the field – probably the St Mary’s entrance path –  and that possibly it stood near to a pronounced dip in the path where the path crossed between two banks. This matched very well with the c1910 photo above, the earliest photograph of the tithe barn we know of. Listening to people recalling from past experience or family memory their stories relating to the tithe barn and where it once stood was rewarding in many ways – it helped us with this project, yes, but it was also sometimes moving, oftentimes fun and always was interesting. We’ll be adding these memories to the project report when it’s next updated so please do get in touch if you’d like to share your own. All of the photos of the tithe barn we had access to at this stage of the project, Winter 2012, can be found on David Allen’s ‘Gamlingay Photos’ website. David, a member of both GamArch and the Gamlingay History Society, would welcome any old photos of our area you might care to share. It was David who took our research  a stage further by overlaying an image of an old OS map on top of an image of an aerial view of St Mary’s field. Using imaging software he then faded the map in and out of view so as to reveal underneath the position of any building mapped by the OS.  David produced a video of this as it happened and you can see the result on YouTube.  At the time the OS map was made only 4 buildings are recorded as lying within St Mary’s field.  Only the most southerly two of the four buildings matched our anecdotal evidence and, arguably, only the southernmost of those two matched the photographic evidence – we had a prime suspect!   However, GamArch became heavily involved in training, fieldwalking and other activites during the Spring and it wasn’t until June and July 2013 that we found time to continue the hunt for the tithe barn. What we did then was to look closely at any old maps of the village we could freely source. Below is a scale plan we made to show the features within St Mary’s field as it would have been toward the end of the 19th century. The plan is based on a 1:2500 scale OS map dating to 1897 and is based on maps viewable at the Old Maps website.So far as St Mary’s field is concerned, the only difference between the 1897 map and the map in David’s video is that the detail of shading in the earlier map is much finer than the 1897 – they are the same two maps to all intents and purposes. Even so, due to the complexities of how old OS maps were produced and published, we can’t be certain there were no changes within St Mary’s field between the dates of the two maps – published maps may be reprints or be based on old survey data, for example. However, a 1:2500 scale OS map dating to 1902 does show there to have been changes within St Mary’s field, the most interesting being a change in shape of our ‘prime suspect’ barn building.

Here’s a plan to scale we made of the 1902 map.

As you can see, the ‘prime suspect’ building on the 1902 map has lost some length as compared to the building shown on the same location in the earlier maps. The reason for the change could be that the building had been rebuilt or somehow modified between the 1860’s and 1902. Notice too that the north west end of the moat is shorter than it once was, it now sitting flush against the field boundary whereas it used to overhang it by several meters. Apart from some minor repairs, old photographs of the tithe barn show it to have remained the same building since at least 1910. Its shape in the photographs also fits well with the ‘chunkier’ version as per the 1902 map so we have no reason to doubt the accuracy of the 1902 map. A more recently published map shows the position and shape of the ‘prime suspect’ to be the same as it was when mapped c1902.

The plan on the right is based on a map of Gamlingay parish given in the RCHM’s volume on West Cambridgeshire, the volume has only recently become freely available online. It’s unclear from the text how the RCHM map was compiled and drawn but it would appear to have relied on OS mapping. If it is OS based, the kink where the field boundaries meet north east of the ‘prime suspect’ is subtly but distinctly different from the 1902 map and so the RCHM map would be post-1902. On all of the maps the position of the ‘prime suspect’ building remains the same, albeit its footprint appears to have changed at some time before 1902. More usefully, the original RCHM map of Gamlingay highlights buildings of interest in the parish and assigns numbers to them, the numbers corresponding with numbered annotations in the text. The main text then discusses each numbered building in turn. Our ‘prime suspect’ is numbered 5 on the map and this is what RCHM has to say about it: “(5) Tithe barn (?), 100 yds. S.E. of the church, now of three aisled bays, framed and boarded, with half-hipped thatched roof. The map of 1601 shows a structure on the site named ‘Tieth barne’. The barn has an entry in the N. bay and may have lost two bays at that end; it is of normal braced tie-beam construction except for long raking struts from the main posts to the aisle ground sill. It has probably been rebuilt in the 17th or 18th century.” So, our ‘prime suspect’ must surely be the tithe barn Gamlingay villagers so fondly remember – we have a result! As to where on modern St Mary’s field the tithe barn stood, David Allen’s video points to it having been situated just north of the path entering the field from the St Mary’s entrance. As to whether or not any trace of it can be found archaeologically, we can turn to some more recent evidence and to a different kind of map, a map of the results of a magentometry survey. During spring and summer of 2013 two remote sensing surveys were conducted in St Mary’s field.  The first of these, conducted by JIGSAW, was a resistivity training exercise for GamArch members. Constrained to an area near to the northern entrance of the field, the resistivity survey didn’t throw any light on the whereabouts of the barn. The second, a magnetometry survey, was undertaken by a commercial archaeology firm on behalf of the Parish Council – there are plans for part of the field to become a new cemetery St Mary’s cemetery to extend into the field and the survey was required so as to meet planning requirements. This survey covered near the entire field and we are grateful to both the Parish Council and to Brittania Archaeology Ltd, the surveyors, for allowing us to reproduce and make use of their illustrations of the result.

What you’re seeing in the illustration left is a map of the magnetic anomalies recorded by the surveyors as they traversed St Mary’s field – you can get your bearings by finding Emplins labelled at top left of the map and the entrance to the field via St Mary’s at the western edge. What the surveyors recorded is differences (i.e. anomalies) in soil magnetism as compared to the backdrop of the earth’s magnetic field. The recorded data can be colour coded according to the strength of the anomaly. This can be printed out as a colour map of the magnetic variation across the area surveyed. If the idea of magnetic soil troubles you, an easy to read guide on magnetometry and why soils have their own magnetic properties can be found here. Next, using mapping and GIS software, we georeferenced the magnetic map and the maps used earlier to produce plans of St Mary’s field and the buildings within and around it. Georeferencing (also known as calibrating) works with digital or electronic versions of aerial photos and paper maps and converts them to a common map standard so that they can be viewed simultaneously at the same scale – so an aerial view can be made to sit in its correct geographical position atop a digital map, for example. On each of our earlier maps we traced the outline of the tithe barn and of the Emplins house outline and added them as overlays to the magnetic map.

The oblong in blue on the above illustration is the outline of the barn taken from the 1897 map, the two black outlines are from the later maps. These overlays on the magnetic survey map all sit in the same location and have the same orientation. Similarly, the Emplins overlays sit in the same location and have the same orientation. How well our own Emplins overlays fit with the survey map’s positioning of the Emplins serves as a check as to the accuracy of our calibrated maps and, therefore, of our overlays. The professional survey map will be accurate to sub-centimeter level and so simple measurement will give us an idea as to how far from true the Emplins overlays are. Whilst their orientation is consistent, the Emplins overlays positionally are all a tad south of where they should be, somewhere between 0.5 and 2.5 meters away from their correct position. Their east-west position is a little better, two traces appear to be alright, one is around 1.5 meters too far east. All in all the position and orientation of the tithe barn as given by the overlays appears to be correct to around plus or minus a couple of meters or so. It’s doubtful we could improve much on that at this stage but we’ll be looking again at the matter and at new resources and will give an update in due course. Meanwhile and aware of the approximate scale of any errors, we’ve looked again at the tithe barn overlays and in how they relate to the purple L-shaped feature on the survey map. When we first saw the survey map it seemed the L-shape might indeed represent the remains of the tithe barn. It was in the area we expected the barn to have stood and its edged shape hinted at the remains of a building. Magnetic surveys are very good at picking up heat-induced changes in the soil such as at kiln sites and so we expected the aftermath of a barn destroyed by fire to be detected by the magnetometry survey. However,the orientation and dimensions of our overlays don’t fit well with the L-shape. Even allowing for errors and presuming the barn to have been far enough east and north of our overlays to fit with the L-shape isn’t entirely satisfactory. The barn in that scenario would then be over other mapped anomolies and surely the barn fire – unattended by the fire brigade –  would have obliterated or masked any pre-exisitng anomalies? Or perhaps the L-shape reflects the way the barn collapsed? As ever, more questions than answers.