The channel between the reef and the coast is in places 70 m.
- For Physical Geography: Barton, Australian Physiography (Brisbane, 1895); Wall, Physical Geography of Australia (Melbourne, 1883); Taylor, Geography of New South Wales (Sydney, 1898); Saville Kent, The Great Barrier Reef of Australia (London, 1893); A.
The Great Barrier Reef of Australia can be traced more or less continuously round the Gulf of Papua and along the south-east coast to the extremity of the Louisiades.
deep. There are a few clear openings in the outer rampart which the reef presents to the ocean.