148 GEOLOGY OF QUEENSLAND COAST, 



Physiography. 



1 . General apj^earance, (he. — From the Tweed Heads to Thursday 

 Island the coast is of the highly indented type, bordered with 

 broad coastal plains. A wide continental shelf exists from north 

 to south, dotted over with innumerable islands, many of them 

 rugged and mountainous in character. 



South of the Great Barrier Reef we have the large islands 

 known as Stradbroke and Moreton, from which to the north and 

 west extend wide coastal plains, especially wide in the neighbour- 

 hood of the Glass House Mountains, which consist of trachytic 

 lavas weathered into most fantastic shapes. 



Further north Frazer (80 miles in length) and Curtis Islands 

 occur, both separated from the mainland by long, narrow, and 

 shallow channels, also accompanied by great sandy flats and small 

 islands. Lady Elliot Island and The Bunkers form the southern 

 outposts of the Great Barrier Reef, and occur a little north of 

 Frazer Island. 



From ]Mackay to Cairns the coast is very nigged. Great 

 mountains advance into the sea; numerous bold promontories and 

 islands such as Cape Cleveland, Cape Upstart, Castle Hill, Cape 

 Grafton, Lion Island, Gloucester, Hinchinbrook, AYhitsunday 

 and Palm Islands are separated from the mainland by long and 

 narrow channels or broad flats a few feet only above high- water 

 mark. 



The flats which gather at the bases of these headlands and 

 coastal ranges are ver}'' conspicuous. 



In many cases these headlands consist of barren rocks, showing 

 a great wealth of enormous precipices and escarpments covered 

 with rounded boulders, illustrating the granitic type of weathering. 



2. Coastal plains. — These are very extensive along the Queens- 

 land coast, and represent the redistribution b)' tidal action of 

 fluviatile material, and to a less extent that derived from the 

 headlands by marine erosion. 



Around Brisbane and the Glass House Mountains these flats 

 are as much as 20 miles in width. To the west the mountains 



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