The Fossil Collection comprises approximately 1,500,000 specimens and is divided into five main categories: vertebrate body fossils, invertebrate body fossils, plant fossils, structures built by bacteria (ie, stromatolites), and trace fossils (eg, trackways and burrows).
Specimens from all continents are represented, although the main focus of the collection is on Western Australia.
Within the vertebrate fossils collection, significant items include:
- 380 million years old, world-renowned Gogo fish fauna from the Napier Range, an ancient barrier reef in Kimberley
- 95 million-year-old (middle part of the Cretaceous period) sharks from the Southern Carnarvon Basin
- Pleistocene (ice-age) megafauna from caves on the Nullarbor Plain.
All three of these areas are the focus of ongoing research by Museum staff, often in collaboration with scientists from other institutions in Australia and overseas.
The invertebrate fossil collection is dominated by molluscs (eg clams) and echinoids (eg sea urchins) from the Cenozoic period (65 – 2.5 million years ago). This focus is largely the result of the accessibility and quality of the coastal outcrops of Cenozoic aged rocks in Western Australia.
The Permian period (300 – 250 million years ago) is also very well represented with crinoids (sea lilies) and sea stars collected from the Gascoyne Junction area in the Southern Carnarvon Basin. The latest Cretaceous (68-66 million years old) Miria Marl in the Giralia Range, Southern Carnarvon Basin is another source of world-class fossil material. It has yielded the world’s richest ammonite (an extinct group of cephalopods) assemblage of this age.
The Museum’s fossil plants collection is mainly derived from three time periods.
- Permian coal seams and sandstones of the Perth and Southern Carnarvon basins contain a rich flora dominated by the deciduous gymnosperm Glossopteris.
- The Early Cretaceous (120 million-year-old) Broome Sandstone in western Kimberley and other, mostly Early Cretaceous units in the Perth, Carnarvon and Officer basins have produced a large number of beautifully preserved leaves, cones, spores and petrified drift wood from ferns, seed-ferns (an extinct fern-like group of plants), lycophytes (club mosses is one of few modern survivors of this group) and conifers.
- The most prolific fossil floras recorded from Western Australia are of mid- to late Eocene age (40 – 35 million years ago) and are found predominantly in palaeodrainage channels on the Yilgarn Craton (very old province of igneous rocks) in the southwest. The climate in this part of Western Australia was still warm and wet in the later part of the Eocene epoch, as indicated by the occurrence of palms and mangroves. Conifers and flowering plants (Gymnosperms) dominate these Eocene floras.
Western Australia’s combined record of fossil and modern stromatolites is without equal. The northern Pilbara region has yielded stromatolite-like structures that are nearly 3.5 billion years old. These may provide some of the oldest evidence of life on Earth. The ancient Pilbara stromatolites have generated more publications in prestigious scientific journals than any other fossil group in the state. Stromatolites declined in numbers and diversity once grazing animals evolved (eg snails). Modern occurrences are mainly restricted to hypersaline lakes and lagoons (too salty for snails), which are environments that are well represented along the coast of Western Australia.
The most significant trace fossils from Western Australia include dinosaur trackways in the Broome Sandstone and traces and trackways from worms, giant sea scorpions and possibly early tetrapods (four-footed animals) in the approximately 400 million-year-old Tumblagooda Sandstone near Kalbarri.