Meeting Report: New Investigations of Roman to Medieval Archaeological Sites in Dumfriesshire
Dr Richard Jones, senior lecturer of the Department of Archaeology of Glasgow University, addressed Dumfriesshire and Galloway Natural History and Antiquarian Society on the subject of 'New Investigations of Roman to Mediaeval Archaeological Sites in Dumfriesshire.'
Knowledge of archaeological sites has advanced by means of aerial photography, field walking and geophysical investigation. The Eastern Dumfriesshire Survey, in which Dr Jones has been involved for the last two years, has been conducted by using geophysics, as employed by the Time Team on television. This last approach is a new element of the survey. His report described work in progress: there is a long way to go before satisfactory conclusions can be reached.
There are different techniques in geophysical study. A magnetometer detects a wide variety of buried features to about one metre in depth: ditches, walls, roads, burnt structures such as furnaces show up on the automatic readings, created as the walker covers the ground. Interpreting the readings is complicated by the fact that other features, such as modern drainage schemes, are also revealed.
It is possible to use two sensors and thereby double the ground covered. A German Company, Sensys, employs a Suzuki to pull a cart with 16 sensors. It operates like a GPS system in vehicles and speeds up the process. The limitation of this last method is that it is expensive and requires flat ground, such as the Roman site studied at Dalswinton.
Resistivity operates on the basis of passing a current into the ground. This method was used at Torthorwald. A mechanised version is in the experimental stage and has not been seriously adopted here.
The third form is ground-penetrating radar, whereby a little black box is pulled along, on which an odometer is fitted to the wheel. There is a transmitter and receiver in the black box. Radar is useful in geophysics because it gives a vertical view from the ground surface down through the ground to 2–3 metres in depth, rather than the horizontal view, which the magnetometer and resistivity give.
Excavations have been conducted over the years at many Roman forts but Dr Jones' team is particularly interested in trying to discover what, in the way of settlements, lies just outwith these sites. Burnswark proved very enigmatic because much of the hill is composed of igneous rock, which has an adverse effect on the conduct of a survey. A small survey was conducted near a small earthwork at Burnswark where traditionally it has been claimed that there was a Roman road: but the geophysical study did not support this claim. At Lochmaben Castle there was very little evidence of definite habitation nearby.
This talk depended on the many illustrations of the geophysical readings for understanding of the attempts at interpretation of each scene. A number of the illustrations were grey and grainy. Dr Jones admitted that to date the survey has touched only the tip of the iceberg. Mediaeval sites are fairly intractable because of agricultural activity conducted in the interim. Dalswinton yielded the best results. Geophysics is not the complete answer and at some point the decision to excavate might have to be taken.