1. Department of Archaeology, University of Exeter, Exeter, EX4 4QE, UK.
2. School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
3. CNRS UNR 5197, Muséum Nationale d'Histoire Naturelle, Paris 75005, France.
4. Carnegie Museum of Natural History, Pittsburgh, PA 15206–3706, USA.
5. Institute for the History of Material Culture, RAS, St. Petersburg 191186, Russia.