Graptolites are a group of extinct colonial hemichordates that floated in Palaeozoic seas or were attached to the sea floor. They have a superb fossil record in Victoria and have been of critical importance in determining the relative ages of rock sequences (by biostratigraphic zonations) within the state.
The graptolite collection contains over 150 000 specimens and is by far the largest and scientifically most important in Australia, containing the greatest diversity of species. This is largely a consequence of the fact that the most important graptolite-bearing Ordovician rock sequences occur in Victoria, and that it was in this state that the Australian subdivision of the Ordovician into nine stages and 32 graptolite zones and subzones was developed.
These graptolite zones have wide application outside Australia, including New Zealand, North America and China. The museum’s graptolite collection is thus of international significance.