GEOLOGY. 225 



during this general subsidence ; and the leaf-beds, with associated 

 clays, bear testimony to them. The relations of leaf-beds, clays, 

 gypsum, and basic sulphate of iron, so frequently observed in 

 Europe, are repeated in the Australian deposits. 



" It is reasonable to admit, especially when the long duration of 

 the time which was occupied by the formation of the series over 

 the fossiliferous deposits is considered, that whilst the vast central 

 area of Australia was a sea, there was open water to the north, 

 with reefs in the Java district, and corresponding formations 

 opened 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 

 part of a great continent; and these marine tracts equalled the 

 terrestrial in magnitude. The greater part of the American con- 

 tinent was submerged, and the Caribbean Sea was a coral area. 

 Where was the bulk of the land when the coral sea stretched 

 round the tropics ? It could only have been to the extreme north 

 and south. New Zealand and South Australia were therefore 

 bounded to the north by a coral sea, and to the south by the deep 

 ocean, as now. So far as the coral fauna is considered, this 

 separation of the Australian sea from the European area by a 

 coral tract inhabited by a distinct iauna, which could only exist 

 under conditions very diverse from those witnessed in Victoria, 

 is explanatory of the comparative isolation of the remote assem- 

 blages of species, supposing them to have existed during the 

 same geological period. The enormous range of deep-sea corals 

 is now admitted ; and it is certainly very remarkable that so few 

 of them should have become common to the European and Aus- 

 tralian tertiary deposits. The absence of any littoral connection 

 between Australia and the tracts to the north of it during the 

 whole of the tertiary period, and the remoteness of the south of 

 its area from any great centres of frequent terrestrial oscillations, 

 may explain the persistence of type which is so characteristic of a 

 large portion of its fauna and flora. This persistence was infi- 

 nitely less in Europe, on account of the more frequent changes 

 in the physical geolog}^ of its area, each change inducing emigra- 

 tion of some forms, unusual competition with others, and occa- 

 sional free scope for rapid multiplication. Hence the distant and 

 comparatively quiet area of Australia was tenanted by the same 

 species, whilst vast biological and geological alterations took 

 place in the area which was formerly considered the type by 

 which all others could be compared. The permanent upheaval 

 of the central and northern area of Australia, the extinction of its 

 volcanoes, and the change in its coral fauna, were grand phe- 

 nomena. 



*' The denudation which occurred during the upheaval of the 

 Australian area was enormous, and it is to be estimated by the 

 extent of the unfossiliferous deposits which cover the fossiliferous 

 marine tertiaries. There are no proofs of any glacial phenomena 

 in Australia ; and subaerial denudation probably went on during 

 the whole of that vast period, and has continued. 



" I would suggest that the word tertiary should be only used 



