Campbell, S., Scourse, J.D., Hunt, C.O., Keen, D.H. & Stephens, N. 1998. Quaternary of South-West England. Geological Conservation Review Series No. 14, JNCC, Peterborough, ISBN 0 412 78930 2.
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In this section, sites are documented which illustrate the Quaternary development of the Somerset lowland and adjacent areas. Two main themes are apparent: marine incursions into the Somerset Levels, and landscape development through the evolution of drainage nets and incision of valleys around the margins of the lowland, particularly in the Parrett catchment to the south of Sedgemoor.
There is still considerable scope for investigations of the marine record in the Somerset lowland, since the complexity of the sequences at localities such as Greylake may have been underestimated by previous workers. Nevertheless, marine and marginal marine sediments attributed to Oxygen Isotope Stage 7 (the Greylake and Kenn Church members at Greylake No. 2 Quarry and Kenn Church, respectively), Stage 5e (the Middlezoy Member at Greylake No. 2 Quarry), and Stage 5a (the Low Ham Member at Low Ham) have been identified and are documented here. The altitude reached by these marine transgressions can be determined; for Stage 7 at Portfield, for Stage 5e at Greylake No. 2 Quarry, and for Stage 5a at Low Ham. These sites are all richly fossiliferous and those at Greylake and Kenn Church provide important evidence for interglacial shallow-marine mollusc communities in South-West England.
A further set of sites documents landscape development around the margins of the Somerset lowland. Key stratigraphic sites in the terrace 'staircase' of the Parrett catchment include the ?Stage 9 site at Hurcott Farm, the Stage 8 site at Langport Railway Cutting, the Stage 7 site at Portfield and the Stage 5a site at Low Ham. Hurcott Farm, Portfield and Low Ham have been dated by aminostratigraphy and thus provide important chronological control in an otherwise undateable sequence. The vastly important site at Broom is perhaps the richest Palaeolithic site in the South-West, and provides important information on the evolution of the Axe Valley in east Devon. The selected GCR sites are all important for the light they throw on the palaeobiology of inland South-West England during the Middle and Late Pleistocene.