Archaeology in the Severn Estuary 15

Iron Age construction methods across the study area are compared with particular reference to the sub-rectangular structures found at Goldcliff. The coastal plains each side of the Estuary were populated by small farmstead type settlements that appear to have had a similar mixed farming economy but only on the Gwent Levels are animal byres used in the exploitation of the wetlands. Earlier hints of cultural difference between the Welsh and English sides of the Estuary have been significantly strengthened. This had largely been seen as being the product of climate variation, with the Welsh climate favouring pastoral activity and the English arable cultivation, although a clear preference for mixed farming economies may indicate this to be more a question of emphasis than clear difference. However, the a ceramic nature of many of the Welsh sites up to the late Iron Age, the creation of upland settlements on an altogether smaller scale than on the English side and the construction of wetland buildings of a form not seen south of the Estuary may suggest cultural differences driven by more than simply adaptation to the environment.

An investigation of the peat beds and submerged forest remains exposed on the present day foreshore of Minehead Bay in Somerset was undertaken following the construction of new sea defences which were thought to pose an increased threat of erosion to the already degraded peat deposits. Radiocarbon dating of peat/clay interfaces, plus the use of a range of palaeoenvironmental techniques allowed the reconstruction of the landscape during the Mesolithic, between c. 5670-4360 cal BC, which appears to have consisted of a mosaic of vegetation communities from marginal salt-marsh, to reed-bed and alder carr with mixed deciduous woodland on the higher, drier slopes of Exmoor. These varied coastal habitats would have supported a variety of wildlife from fish and wildfowl to larger animals like the now extinct aurochsen which would have grazed on the saltmarsh. Possible burning of the reed-swamp, perhaps accidentally from camp fires or perhaps as a deliberate attempt to alter the environment, is suggested from remains of Graminoid charcoal, likely to be Phragmites. A few flint tools were found during earlier surveys of the bay, including axes and scrapers, and these demonstrate that people were taking advantage of these natural resources.

The 1607 coastal flood was a high magnitude event that may have been the result of either a storm surge or a tsunami wave(s). Contemporary accounts describe the impacts of the surge/wave at Appledore and Barnstaple in North Devon, and a 19'h century comment exists for Hayle in Cornwall. An examination restricted to these local accounts reveals that the surge altitude or tsunami run-up at Appledore, at the estuary mouth, exceeded 8.5 m OD (a surge/wave height in excess of 3.28 m, possibly up to c. 7-8 m), and at Barnstaple, about 12 km up-estuary it reached 7.53 m OD (a surge/wave height of 1.83 m). Damage included houses 'overthrown and sunk' at Appledore and a number destroyed at Barnstaple where there are three named fatalities. Also, a 60 ton ship was transported inland by the wave at Appledore. Most of the contemporary accounts mention strong winds, supporting a storm origin for the flood; however, an unpublished model requires hurricane winds of 128. 7 kmh (80 mph) to reconstruct the observed flooding. Such winds alone would result in widespread damage and casualties, inland as well as at the coast, but there is no mention of either in any historical document that we have seen, indeed, contradictory accounts from the Severn Estuary state the day was 'most fayrely and brightly spred'. The ambiguity of the regional meteorological conditions, the lack of documentary evidence for hurricane winds, and the nature of the damage inflicted do not allow us to reject the tsunami hypothesis for the origin of the 1607 flood.

This paper surveys the strong position of maritime archaeology in Denmark during the period 1993- 2003, and briefly discusses the relevance for the situation in the Severn Estuary region.