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Winscombe Archaeology

A Roman road from Loxton towards Banwell through the Lox-Yeo valley

 

A geophysics survey by ALERT in May 2009 identified a linear feature over 100m long and about 12m in width which has been interpreted as the remains of an agger of a Roman road. The earthwork is barely visible on the ground and lidar images give only a faint indication of its presence.  

 

 

 

 

 

 

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Geology

The feature (GR ST 389 575) runs across a slightly elevated area which is probably the remains of a deposit on the inside bank of an old course of the Lox -Yeo River where it leaves the Vale of Winscombe and turns south towards the River Axe.  The river now cuts between this deposit and the red marl to the south, but periodic flooding both from changes in sea levels and increased water flow from the Mendips must have caused the river to change its course many times over the millennia. The esturine alluvium deposits of the valley bottom (about a metre lower) surround this colluvium on three sides.

 

 

 

 

Figure 1

The Lox-Yeo Valley showing the postulated course of the Roman Road. The arrow indicates the section surveyed at ST 389 575.

 

 

The survey

The area was surveyed using a Bartington 601 single pole gradiometer and a TR/CIA resistance meter. The gradiometer results were disappointing probably because of the alluvial nature of the deposits. The resistivity survey identified a feature running from southwest to northeast which was at first though to be geological. An examination of the bed of the adjacent river confirmed the presence of layers of red sandstone and limestone above which the alluvial matter had been deposited. These rocks had been laid down on a different orientation to the linear feature and are 2m below it. The survey was therefore recording data on the surface the alluvial deposit. The ground resistance survey showed a straight line of high resistance 10m wide and over 100m in length. A line of lower resistance either side enabled the Team to postulate the presence of ditches either side, each about 2m wide. Along the centre line of the feature there appears to be a broad, shallow depression running for most of the length.  A resistivity ‘section’ of the feature suggested that the cross section of the feature was lens-shaped and between 50cm and 75cm deep at its thickest in the centre. An attempt to follow the line of the feature on to the esturine alluvium of the valley bottom to the northeast was not entirely successful, probably due to the depth of this deposit, but two very faint parallel diverging sets of ditches were recorded, one pair of ditches 10m apart and the other 14m apart.

 

 

 

 

 

Figure 3

Top. A ground resistance transect of the road. The two ditches can be seen at 3m and 16m. The higher resistance between them indicates the denser material of the agger.

Bottom. A resistivity ‘section’ of the road. The ditches (green spikes) match with those shown above. The agger can be seen as a lens of higher resistance (dark red). This method of survey can illustrate the depth of deposits, but it is not able to show the slight rise in ground level above the agger.

 

 

 

Figure 2.

The resitivity survey showing an 80m length of the road.