INTRODUCTORY. 3 



The numbers in the above list associated with an asterisk indicate the only passages which 

 are regularly used for navigation. Out of these, No. i represents the ordinary entrance through 

 the Barrier of vessels of heavy draught proceeding from the east by what is known as the 

 Outer Route, vici Torres Strait, to India and China. The Raine Island Passage, No. 6, prior 

 to the surve}' of the Great North-East Entrance, represented the main route from the east and 

 south to Torres Strait ; in consequence of the intricate and dangerous nature of its reefs 

 and channels it is now, excepting for its occasional use by small craft, practically abandoned. 

 Nos. 12 and 14 are commonly utilised by vessels sailing between Cooktown and New Guinea. 

 Nos. 16 and 17 'Afford convenient entrances to the ports of Cairns and of Geraldton, while 

 Capricorn and Curtis Channels represent the wide navigable openings through which all vessels 

 from the south gain entry, proceeding by what is known as the Inner Route to Torres Strait, 

 the Indian Ocean, and China Seas. 



The linear chain of reefs that form the outer edge of the Barrier, together with the in- 

 numerable secondary reefs that are congregated closely within its boundaries, constitute a 

 natural breakwater against the ever-reverberating surges of the Pacific Ocean, and thus convert 

 the "Inner Route" into a relatively shallow and tranquil inland sea, which the largest ocean 

 steamers traverse, for the greater part of the year, with open ports and on an even keel. This 

 inner passage being thickly studded with islets, reefs, and shoals, its navigation is necessarily 

 intricate, and gives employment, where vessels of heavy tonnage are concerned, to a large 

 staff of experienced and highly efficient pilots. All danger in this inner passage, it is scarcely 

 necessary to remark, is further reduced to a minimum by the very excellent system ot lighting 

 and beaconing that has been established by the Queensland Government. For the introduction 

 and organisation of the system, special credit is due to Captain G. P. Heath, R.N., who recently 

 retired, after having been Port Master to the colony for a period of thirty years. The lighting 

 and beaconing of the Queensland coast-line is, as a matter of fact, frequently cited by navigators, 

 the world over, as among the most efficient of its kind. 



Further data concerning the structural features of the Great Barrier Reef, together with a 

 summary and a discussion of the theories that have been most recently advanced with relation 

 to the origin of coral formations, furnish the material for a separate chapter. 



B 2 



