Geophysics Training Weekend - Twelve Go Mad in Holystone
Well, that's what it must have looked like anyway! On a weekend in November about a dozen members of the Holystone History Group turned up to learn more about the weird and wonderful world of geophysical surveying from a team from Durham University Archaeological Services.
At least the weather was perfect – blue skies, no rain and not too much wind – as we'd set ourselves the challenge of trying to find the exact route of the Roman Road which, according to all OS maps, used to run right past the Holy Well. At the time it seemed like quite an easy task, but, as we were soon to discover, nothing in archaeology is ever easy...
Geophysics at Holystone
The good tempered and patient Durham University team took us in hand and showed us the basics of two types of geophysical surveying – the resistivity method and the magnetic one. First of all, the area to be surveyed had to be laid out according to a grid system first, so it would be possible to pinpoint the exact location of any "find". Then the fun really started…we soon learned that using a magnetometer machine, which detects deviations in the sub-soil according to variations in the magnetic field, was a much quicker enterprise, as you just drape the machine across your body and walk up and down the grid whilst it beeps contentedly back at you. Resistivity survey, on the other hand, takes forever! This method sends an electric current through the sub-soil between electrodes, measuring any resistance to its flow, and involves sticking probes into the ground every half metre - a long, slow process.
Once dusk fell, we retired indoors to download all the survey information from the machines into a handy lap-top computer. Sadly, neither the resistivity nor the magnetometry survey showed up anything looking even remotely like a Roman Road.
Totally undeterred, we returned the following day to try the field to the north-east of the Holy Well. This time we worked much faster – we'd really got the hang of this surveying lark by now – and soon finished the area marked out. So back to the lap-top to download the data – once technical hitches were overcome by the undaunted Dave Robinson, the results were clear to see…but again, no sign of the Roman Road!
So what do we conclude? well, there are a number of reasons why we may not have found the course of the road – perhaps we were looking in the wrong place, or perhaps the road has been completely destroyed by medieval rig and furrow ploughing, which is clearly visible on the surface of the field.
However, all is not lost! When the team back at Durham analysed the results of our weekend's work, they were thrilled to see the shadowy outlines of several circular shapes in Cocklaw Bush field. It is possible that these are ring ditches, the remains of prehistoric houses or burial sites, and so even older than any Roman activity in the area. So, as always, archaeology is always full of surprises, and even if you don't find what you are looking for there seem to be tantalizing clues to the past everywhere you go!
Jan Frazer, Holystone History Group
Click here to read the full Holystone Geophysics Report (PDF format, 4.5MB)
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