11 
fine natural mud-cast of Nautilus geelongensis from the 
Miocene of the Orbost district should here be noted. The 
giant Ammonite-like forms are represented by Crioceras 
and Ancyloceras from the Cretaceous of Queensland. 
Amongst the Gasteropods or Univalves, the Giant Cowrie 
(Cypraea gig as) from Muddy Creek and the enormous Volutes 
(Pterospira validicostata ) are conspicuous. Of the Bivalves, 
the Oyster (Ostrea) is common in the fossil condition, forming 
oyster beds in the limestone deposits of Dartmoor, Bairnsdale, 
and Cape Otway, examples of which shells are shown here : 
some of these are indicated by their great thickness of shell- 
plates or lamellae to have been quite 100 years of age when 
covered by sediment. 
The Hydroids (allies of the living “ Sea-firs ”) are 
represented by some fine Graptolites (from graphe, I write ; 
lithos, a stone), on slabs of slate from Lancefield, Bendigo, 
Fig. 11. Goniograptus speciosus T. S. Hall. 
A Graptolite from the Lower Ordovician. 
Black Forest, south-west of Woodend, Victoria. 
