1. Department of Geology, University of Leicester, Leicester LE1 7RH, UK
2. Department of Geology & Geophysics, Yale University, PO Box 208109, New Haven, CT 06520-8109, USA
3. Peabody Museum of Natural History, Yale University, PO Box 208118, New Haven, CT 06520-8118, USA
4. Geological Collections, University Museum of Natural History, Oxford OX1 3PW, UK
5. Department of Earth Sciences, University of Oxford, Parks Road, Oxford OX1 3PR, UK
6. Department of Earth Sciences and Engineering, Imperial College London, London SW7 2BP, UK