doi:nature07673 LETTERS Fossil steroids record the appearance of Demospongiae during the Cryogenian period Gordon D. Love1,2, Emmanuelle Grosjean3, Charlotte Stalvies4, David A. Fike5, John P. Grotzinger5,

First Page		Document Content
Date: 2009-02-03 10:38:36		doi:nature07673 LETTERS Fossil steroids record the appearance of Demospongiae during the Cryogenian period Gordon D. Love1,2, Emmanuelle Grosjean3, Charlotte Stalvies4, David A. Fike5, John P. Grotzinger5, Add to Reading List Source URL: www-eaps.mit.edu Download Document from Source Website File Size: 356,47 KB Share Document on Facebook