PREFACE, 
understanding of the relations of which strata to each other, and to 
corresponding deposits in other parts of the world, can only be 
arrived at by the identification of their organic remains ; a know- 
ledge of which will also materially assist the operations of the field 
geologists at present engaged in mapping these formations, and 
testing the theories relating to the oceurrence of gold in the 
different stages of each of those geological periods. 
The first and second plates give illustrations of the skull and 
teeth of a new extinct species, of Eared Seal, from the Pliocene 
Tertiary calcareous beds at Queenscliff ; nearly related to the living 
Otaria and Arctocephalus of our southern seas. 
The third plate illustrates some of the more abundant and 
characteristic Brachiopoda of our Tertiary strata, one of them 
completely identical in size and shape with the recent Waldheimia 
Australis of our Bay, but the smallest fragment of which I find 
may be discriminated specifically by the larger size of the pores 
viewed with a strong lens. 
The fourth plate is devoted to illustrations of two Tertiary 
species of Cardiwm, one of them so nearly related to the Upper 
Eocene or Oligocene Tertiary Cardium semigranulatum of the 
Bracklesham Bay beds of the Hampshire coast and the Isle of 
Wight, that none of the existing figures or descriptions of the best 
authors could enable the distinction to be recognised which I have 
pointed out based on the usual careful comparison of specimens 
from both localities. 
The fifth plate gives further illustrations of the Spondylus 
gederopoides, the Australian representative of the well-known 
Europeau Tertiary and recent Spondylus gederopus; and an 
additional Victorian smaller and rarer extinct species. 
The sixth and seventh plates are filled with figures of species of 
Upper Silurian Mollusca, of the more abundant forms characteristic 
of this formation ; of the Mollusca of which we have not previously 
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