Affiliation: | 1 British Geological Survey, Keyworth, Nottingham NG12 5GG, UK 2 Scops Geological Services Ltd, 31 Periton Lane, Minehead, Somerset TA24 8AQ, UK 3 Network Stratigraphie Consulting Ltd, Harvest House, 2 Cranborne Industrial Estate, Hertfordshire, Potters Bar EN6 3JF, UK |