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abound. The species of the different beds have so great a 

 general resemblance, that they do not offer evidence of any 

 biological changes during the deposition of the whole. He 

 points out that it is inconsistent with the rules of geological 

 classification to subdivide the series into Oligocene, Lower, 

 Middle, Upper Miocene and Pliocene, which iu Europe have 

 very distinct fauna. The percentage system cannot yet be 

 applied to Australian beds, as the Mollusca existing are so 

 little known, and a comparison of the corals would make them 

 older than the evidence of the physical geology warrants. 

 There was evidently in these periods much disturbance and 

 alteration of currents in the sea bottom, formed of Silurian 

 rocks, basalts, and carbonaceous sandstones ; conglomerates, 

 pebbly sandstones, clays and clayey sandstones alternated 

 under different conditions during a vast period of subsidence 

 connected with the outpouring of trap rocks, covering littoral 

 deposits and the gradually denuded rocks. The leaf beds 

 show temporary upheavals. The relations of the leaf beds, 

 clays, gypsum and basic sulphate of ii'on, so frequently seen 

 in Europe, are repeated in Australia. The chemical decora- 

 position of these beds accounts for their contortion. No other 

 disturbance is manifested in Australia in which the beds 

 contrast with the changes to which the tertiaries of the West 

 Indies, Europe and Sindh have been subjected. 



Dr. Duncan thinks that during the long duration of time 

 during which Australia was a sea, there was open water 

 to the north, with reefs in the lava district and corresponding 

 formation, opening into what is now the Mediterranean, and the 

 Sahara to the north-west. The Indian peninsula, and the area 

 now occupied by the Himalayas, and stretching far away to 

 the east, were not a part of a great continent. The greater 

 part of the American continent was submerged, and the Car- 

 ribean Sea was a coral sea. He then suggests that the 

 bulk of land must have been to the extreme north 

 and south of the globe. Australia and New Zealand, 

 he adds, were bounded on the north by a coral sea, and on 

 the south by a deep sea, as now. In this way he accounts for 

 the persistence of earlier types in Australia, and its perfect 

 disconnection from Europe in its present and existing fauna 

 and flora. Eor though corals are known to have an enormous 

 range, very few are common to Australian and European 

 tertiaries. " The absence of any littoral connexion between 

 Australia and the points to the north in the tertiary period, 

 and the remoteness of the south of its area from any great 

 centres of frequent terrestrial oscillations, may explain tho 

 persistence of type." This persistence was infinitely less in 

 Europe on account of the more frequent changes in its physi- 



