Introduction
We were invited to evaluate the geoarchaeology of a site at Redland Court Road, Bristol, to help the excavating archaeologists, both in understanding the origins of the deposits and in assessing the archaeological potential of the site.
Background
The bedrock of the area was known to be calcareous clay with limestone and we found the soils on the site to be clayey, seasonally waterlogged and slowly permeable. The site lay on the gently sloping brow of a hill, which sloped away at an increasingly steep angle to the north east. It is this gentle slope together with the slow drainage of the underlying clays that helps keep the soils wet. At the time of our visit, the site was used for playing fields and tennis courts, but has also been used as agricultural land and allotments.
A number of trenches had been dug across the site and had been positioned based on information from a geophysical survey, and it was in these trenches that we examined deposits, visible in the sides of the trench, and took samples for later analysis.
Findings
In the lower half of one of the samples we looked at, we found a relict blocky structure, which was possibly caused by the deep rooting from the hedge of a former field boundary. In another sample we could see the outlines of three ditch-like features, one on top of the other. These features appeared to run along the line of another former field boundary, two of them were without doubt ditches, the third and lowest however, was again caused by deep rooting from the hedge of the former field boundary. The deeper rooting had mixed down into the deposits darker organic matter from above creating the impression of a ditch-like feature.
Conclusions
From our investigations, were we able to tell the excavating archaeologists, that the lack of archaeological evidence and the poor survival of geoarchaeological evidence meant that no further study would be worthwhile. We were also able to highlight the importance of understanding the effect of deep, concentrated rooting on deposits, and how this effect could be wrongly believed to be the result of human activity when in reality it is quite natural.