1. Stratigraphy Group, Department of Earth and Ocean Science, University of Liverpool Brownlow Street, Liverpool L69 3BX, UK david.hodgetts@man.ac.uk
2. Now at Department of Earth Science, University of Manchester Oxford Road, Manchester M13 9PL, UK
3. Schlumberger Cambridge Research High Cross, Madingley Road, Cambridge CB3 0EL, UK
4. Statoil ASA, TEK F&T UTV TOS Forushagen, 4035 Stavanger, Norway
5. Department of Geology, University of Bergen Allegaten 41, N-5007 Bergen, Norway