Abstract
Gwithian is a multi-period archaeological site on the north coast of Cornwall in the south-west of Great Britain. It lies at the mouth of the Red River, within St Ives Bay, the westernmost sandy stretch of the Bristol Channel coast of the south-west peninsula. This location made the site an attractive locus for settlement, and excavations by the late Professor Charles Thomas since the late 1940s have revealed evidence for human activity dating from the Mesolithic period to the present day. In recent times, the wider landscape has been subject to intensive mining for tin and other minerals, the ochre released from which gave the Red River its name. A calcareous sand dune system and associated areas of blown sand encompasses part of the site, and since the 1970s this has been subject to a number of palaeoecological studies focused on the non-marine mollusca preserved in the sand.
This book presents the evidence of the most recent investigation of this landscape, a multi-proxy archaeological and palaeoecological study, and is derived from Walker’s doctoral research at the University of Reading. The investigation included a ground-penetrating radar survey, a coring transect using both petrol-driven percussion cores and a hand-operated gouge auger, hand excavated trenching and sampling of eroding sections at the shore. In addition to the molluscs of the title, laboratory investigations included diatom assessment and geoarchaeological techniques such as particle size analysis, pH estimation and loss on ignition, as well as x-ray fluorescence (XRF) using an ITRAX core scanner. The chapters on pollen analysis and thin section soil micromorphology are contributed by Rob Batchelor and Rowena Banerjea, respectively. The study includes 19 new radiocarbon dates, and 5 new optically stimulated luminescence (OSL) dates.
This impressive array of techniques allows Walker to draw some significant conclusions about the changing environment at the site. The timing of episodes of aeolian sand movement is refined. The earliest evidence for sand blow outside of the valley basin is during the middle to late Neolithic, whereas in the river valley it occurred in the early Bronze Age. A field system at Strap Rocks to the south of the Red River was overwhelmed with sand in the middle Bronze Age.
The coring transect through the Red River valley reveals no evidence for marine estuarine conditions in the northern side of valley adjacent to the settlements. Combining his evidence with that of earlier borehole surveys, Walker suggests three phases of changing tidal extent in the valley, the earliest extending up to 1 km inland, and two further phases of successive regression. The use of XRF on the cores from the river suggests that it was from about AD 1050–1100 that mining residues turned the river water red. Readers of The Holocene may find the suggested method for calculating compression of silt layers in cores caused by percussion coring of particular interest.
The trench excavation reveals evidence for the Bronze Age ploughing regime, which is enhanced by micromorphological study, while the presence at the site of the blue-rayed limpet Patella pellucida strongly suggests the use of seaweed as a consolidant and fertiliser on the fields. The site is one of relatively few in the UK, where successive layers of blown sand preserve footprint-tracks of cattle and sheep or goats.
The wealth of new dates allows some revision of our understanding of British molluscan biogeography. An undergraduate dissertation by Penny Spencer (1974) in the 1970s had drawn attention to unusual shells in the prehistoric sections, tentatively identified as ‘Candidula cf. intersecta’, which were subsequently identified as Xerocrassa geyeri (then called Trochoidea geyeri) by Annie Milles (1991) in the early 1990s. Either determination would be unusual: C. intersecta is thought to have arrived in the British fauna during the medieval period or later, while X. geyeri is essentially a cold climate snail which disappeared from Britain early in the Holocene. Drawing on the expertise of Dr Edmund Gittenberger, Walker confirms the latter identification, extending the survival of X. geyeri at this site at least until as late as 1650–1500 cal. BC.
Cochlicella acuta is a snail particularly associated with dune systems, which was thought to have arrived in south-west Britain in the late Bronze Age, spreading northwards and reaching the Western Isles of Scotland early in the Iron Age (Davies, 2010; Law and Thew, 2017). New dating at Gwithian suggests that it was present at the site as early as the late Neolithic, however, likely attesting to trading links with the continent at this time.
Seven of the radiocarbon dates are from shells of Cochlicella acuta, and six from shells of Xerocrassa geyeri. The close correspondence of some of the former with a radiocarbon date on Prunus sp. charcoal gives hope that the species does not suffer from old carbon effect and is suitable for dating, although a discrepancy between a radiocarbon date on a C. acuta shell and an OSL date from the core samples in Chapter IX is not discussed. Deviations between radiocarbon dates on X. geyeri shells and OSL dates from the trench excavation are very plausibly explained by site formation processes, however.
The book is well produced in paperback, with clear and helpful colour illustrations throughout and a judicious use of photographs and tables. Typographical errors are minor and very few, although the erroneous species name Sambucas (sic) nigra appears throughout, and there is some inconsistency in terminology, with Figure 30 referring to ‘percussion cores’, while Figure 32 refers to ‘Cobra cores’. A puzzling reference to ‘Costataeidae’ appears on page 49. Although the subject matter is undoubtedly technical, the writing is clear, precise and, importantly, accessible throughout.
The Gwithian Landscape is an impressive example of a well-devised and thoroughly executed archaeological and palaeoecological research project, which makes a significant contribution both within and beyond the geographical limits of its study area. It will undoubtedly serve as a useful template for future project design at coastal sites.