Victorian Marine Fossils

Marine rocks in Victoria

By far the most common kinds of fossils found in Victoria are those of marine creatures, which are found in nearly all of the rocks that were deposited in the sea in past ages. The oldest of these marine rocks in Victoria were deposited during the Palaeozoic Era, 545 to 251 million years ago (mya). They form the highlands of the state, extending from the Grampians in the west to East Gippsland, and also occur in the eastern suburbs of Melbourne. Much younger rocks, formed between 65 and 1.78 mya during the Tertiary Sub-era, also contain marine fossils. These younger rocks occur along almost the entire southern coast of Victoria as far east as Orbost, including the eastern side of Port Phillip Bay and in the Geelong area.

Fossil sea star (Eoactis stachi), Late Silurian (c. 420 million years old), Melbourne, Victoria
Photographer: Rodney Start. Source: Museum Victoria

Common types of fossils found in Victoria

Fossils of many different kinds of marine animals can be found in Victoria. Some of these represent kinds of animals that are now extinct, but others belong to groups that are still common and familiar in the sea today.

	Trilobites are crustacean-like animals that were one of the most numerous and successful marine creatures of the early and middle Palaeozoic. In Victoria, trilobites are common only in middle Palaeozoic rocks in central Victoria.
	Brachiopods are a type of marine shellfish with the soft body enclosed in a pair of shells that can be opened to enable the animal to feed and breathe. Living brachiopods still exist in the sea but they are not often seen. Fossil brachiopods, however, are very common in middle Palaeozoic rocks of central Victoria and in Tertiary limestones.
	Corals were abundant during the Palaeozoic Era but they belonged to different types than those living today. Their fossils occur in Palaeozoic siltstones and limestones in central Victoria. Corals found in Tertiary limestones and clays, such as around Mornington, are of the same type as living forms.
	Echinoderms, like corals, are still in existence and include the familiar sea urchins and sea stars as well as less familiar groups. Sea stars, crinoids and some extinct groups of echinoderms are found in the middle Palaeozoic rocks of central Victoria. Sea urchins are common in Tertiary limestones, for example at Torquay and Lakes Entrance.
	Molluscs are represented in present-day seas by such groups as the bivalves, which include clams, mussels and scallops; the gastropods, or snails; and the cephalopods, including octopus, squid and cuttlefish. Fossil molluscs are very common in Tertiary rocks in Victoria but also occur in Palaeozoic rocks.
	Bryozoans are a group of mostly marine animals living in frond- or coral-like or colonies. They are very common today but many people mistake them for seaweed or corals. Bryozoans were so abundant during the Tertiary that some limestones are made up entirely of their broken skeletons. Fossil bryozoans also occur in rocks of Palaeozoic age.
	Graptolites are extinct marine animals that formed twig-like colonies composed of one or more branches. They are one of the most important groups of fossils for dating early Palaeozoic rocks. Rocks of this age in central and eastern Victoria contain one of the richest graptolite assemblages in the world.