288 The Realm of Nature CHAP. 



coasts reduce the width to 1 1 oo miles in the narrowest part 

 of the continent, while both the east and west coasts form 

 bold outcurves. Tasmania rests on the Continental Shelf 

 to the south, and New Guinea to the north. The average 

 height of the land, as far as can be judged from the imper- 

 fect exploration of the interior, is about 800 feet. In spite 

 of this low elevation the proportion of land less than 600 

 feet above the sea is small, while the proportion between 

 600 feet and 1500 feet in elevation is greater than for any 

 other continent. 



371- Configuration of Australia. The continent is 

 apparently one low plateau, rising into a line of hills along 

 the west coast, and ridged irregularly here and there by 

 mountains in the nearly unknown interior. It sinks in the 

 south-east to an extensive low plain (the Australian Basin) 

 less than 600 feet above the sea. Half of Australia is 

 made up of areas of internal drainage. The Great 

 Dividing Range, forming the axis of the continent, rises 

 along the eastern edge. It sweeps round the south-east 

 coast under the name of the Australian Alps, and cul- 

 minates in Mount Townsend or Kosciusko (7300 feet). 

 Thence it runs northward under different names as a 

 chain of short ranges, scored by deep transverse valleys, 

 sending short full rivers to the Pacific. Diminishing in 

 height toward the north, it merges into the general eleva- 

 tion of the plateau. The ranges were, as a rule, ridged up 

 out of primary rocks, the Silurian system being now most 

 prominent in the south, and the Carboniferous, with thick 

 seams of coal cropping out, farther north. Gold, and the 

 ores of silver, tin, and lead occur in great abundance. 



372. River Basins. The southern part of the Dividing 

 Range slopes down very steeply westward to the low plain 

 of the Australian Basin. The Murray River flows westward 

 across the Basin from its source near Mount Townsend, and 

 after receiving the Lachlan and Darling it swerves to the 

 south and enters the sea. Many long rivers are marked on 

 maps converging from the east and north to the Australian 

 Basin, but most of these are stony channels only occupied 

 by water after rain, and many of the streams dry up as they 



