I knew someone would correct me if I was wrong. Thanks Dave. Hadn't known that, it was good to learn! Tara -- ______________________________________________________ Tara Deen School of Geosciences Division of Geology and Geophysics Building FO5 University of Sydney NSW 2006 AUSTRALIA Phone: 61-2-9351 4271 Fax: 61-2-9351 0184 Mobile: 061 410 538 655 email: tara@es.usyd.edu.au ______________________________________________________