b PRESIDENT S ADDRESS. 



It is certain that, even then, it extended considerably more to 

 the eastward than at present, and that in the west there existed 

 a range of high mountains, from the wear and tear of which the 

 strata of the lower lands were formed. 



A great basin, over the centre of which Sydney now stands, 

 and which extended from beyond Newcastle on the north to 

 Shoalhaven on the south, and from beyond Hartley on the west 

 to a distance of 70 miles or more to the eastward of the present 

 coast line, then existed, and in this basin was formed the immense 

 mass of coal which is of such incalculable value to New South 

 Wales. 



This basin gradually subsided, during the formation of the 

 coal; and, in the Triassic period, sank beneath the Pacific Ocean. 

 This subsidence may have been caused wholly or partially, firstly, 

 by the pressure on the semifluid underlying matter, of the 

 accumulations of vegetable matter, which were ultimately con- 

 verted into coal, and secondly, by the constant sinkage of cool 

 water, which would have the effect of contracting the heated 

 matter lying below. 



In the vicissitude of things, the eastern half of the submerged 

 basin was cut off and permanently lost, though the residue, con- 

 solidated by the deposition of the Hawkesbury sandstone, after- 

 wards rose again, but again sank so as to allow the deposition of 

 the Wianamatta shale above the sandstone and the deposition of 

 the Cretaceous beds of Triassic age in Queensland, South Aus- 

 tralia, Western Australia, and the north-west portion of New 

 South Wales. 



Finally, the remnant of the great basin again rose in the 

 Tertiary era, since which there has been no further sinkage of 

 any importance. Wallace supposes that Australia, being an 

 ancient continent of Quaternary or Tertiary age, is gradually 

 decreasing in size, as indicated by the gradual subsidence of 

 New Caledonia and certain other South Pacific islands. 



After the loss of the eastern half of the coal basin, the east 

 coast of New South Wales stood at about twenty miles eastward 

 of the present coast line, but it has since been gradually cut into 



