![Bivalve-Mollusc](http://fossilsaustralia.com/wp-content/uploads/2013/04/Deltopecten-Bivalve-Mollusc.jpg)
Marine bivalve mollusc filter feeder lived in shallow marine environments attaching themselves to rocks or hard surfaces. They have compressed bodies enclosed by a shell in two hinged parts and are similar is shape to the Shell Oil logo and are related to clams, oysters, mussels. Specimen from the South Coast of NSW.
http://en.wikipedia.org/wiki/Bivalve_molluscs