THE AUSTRALIAN GREAT BARRIER REEF. iii 



Following the inner route along its north-westerly course for another seventy miles, no 

 other island group of primitive rock formation is encountered. The outer edge of the Great 

 Barrier has, from its greatest distance from the mainland (one hundred and fifty miles off the 

 Swain's reefs) trended gradually inwards, and is now, opposite Cape Bowling-Green, within the 

 narrower, but still considerable, distance of fifty miles from the Queensland coast. At this 

 particular point we arrive at the third considerable, or navigable, gap in the Barrier, which 

 has received the name of Flinders' Passage. The Curtis and the Capricorn Channels, at the 

 extreme southern limits of the Great Barrier, have been enumerated as conr.tituting the first 

 and the second passages. There is a feature of interest associated with Flinders' Passage 

 and the two more southern Barrier openings, to which brief attention only will be drawn 

 at this point, whose most important significance is reserved for future notice. This is 

 the mouth of a river, the Burdekin, having an extensive watershed, immediately opposite 

 Flinders' Passage gap. The watershed to the south, adjoining that of the Burdekin, is of much 

 more considerable dimensions ; it drains all the back country for an approximate superficial area 

 of 40,000 square miles, in the united streams of the Mackenzie, Comet, Dawson, and Fitzroy 

 rivers, and discharges itself into Keppel Bay, immediately opposite the wide portals of the Capricorn 

 Channel. The next watershed of any importance, farther south, is that of the Burnett River, 

 whose estuary immediately faces the Curtis Channel. 



Fifty miles more sailing in the same north-westerly course, after leaving the parallel of 

 Cape Bowling-Green and the Flinders' Passage, brings the voyager abreast of the Palm Islands, 

 he having previously, some ten miles back, passed Magnetic Island, a short distance off the 

 coast, in the neighbourhood of Townsville, Queensland's northern capital. With the excep- 

 tion of this island, and Hobourne Island and Nares Rock off Cape Gloucester, the entire 

 distance, about 150 miles, between the Whitsunday and Palm Islands groups, is uninter- 

 rupted by any elevated rocks or islands of metamorphic or stratigraphical nature. Archi- 

 pelagoes of coral-reefs and shoals abound, however, as throughout the superficies of the Great 

 Barrier region. 



Some half-a-dozen islets are included in the Palm Islands group. They occupy an area 

 ranging from ten to twenty miles off the mainland coast; and their abundant fringing reefs 

 have, as in the case of those of Port Denison, been extensively utilised for the illustration of 

 this work. The Photo-mezzotype Plates Nos. IV., VI., X., and XXVIII. yield fair evidence of 

 their diversity of aspect and composition. The collection of coral specimens made on these 

 reefs was very considerable, and included many types that were not obtained farther south. 

 The genera Oculina, Echinopora, and Tridacophyllum are especially noteworthy. Of the genus 

 Madrepora, or Stags'-horn corals, some thirteen specific forms were collected, comprising 

 the brilliant electric-blue variety of Madrepora laxa, represented by Plate IX., Fig. 6, of the 

 chromo-lithographic series. 



