AGASSIZ: THE GREAT BARRIER REEF OF AUSTRALIA. 131 



Great Barrier Beef by W. Saville Kent ; * and, finally, a number of refer- 

 ences by travellers to the Great Barrier Beef, in which the authors either 

 adopt or reject the theory of subsidence as explanatory of its formation, 

 without however giving any new facts bearing upon the subject. 2 



We need only discuss the views of Jukes and of Kent in the light 

 of the observations made on the " Croydon " during my visit to the 

 Great Barrier Beef. 



Jukes's description of the " First Bunker's Island," in the northern part 

 of the Capricorn group, 3 remains to-day an excellent description of a 

 pseudo atoll such as are common on the isolated reef flats of the Great 

 Barrier Beef. Kent copies this as Jukes's description of Lady Elliot 

 Islet. 4 This certainly is a mistake, as the " First Bunker's Island " is in 

 the northern part of the Capricorn group, and " twenty-five miles north- 

 west of Lady Elliot Islet." 5 



Jukes has, it is true, given a sketch of Lady Elliot Islet, but it 

 has nothing to do with his description of " First Bunker's Island." 

 On page 4 he mentions anchoring between " the third or northern 

 Bunker's Island " and " a large coral reef with a shallow lagoon and 

 a small patch of dry sand on its western side." This is probably 

 Bo alt Reef. 



Kent, on p. 106, has copied Jukes's description of "One Tree Island" 

 and of " Heron" Island. Jukes was greatly puzzled regarding the mode 

 of formation of hardened coral rock greatly weathered which forms what 

 subsequent writers have called " beach rock " in coral areas. Jukes 

 speaks of its surface as everywhere rough, honeycombed, and uneven, 

 dipping toward the reef at an angle of 8° or 10°. He has described 

 this beach l'ock from Heron Island as well as from Wreck Island. 



Kent has also reproduced (p. 109) Jukes's account of one of the reefs 

 belonging to the Swain group which Jukes explored, sailing about eighty 

 miles north and south along the eastern edge, and ninety miles right 

 through them in a west-southwest direction, passing through narrow 

 channels from ten to thirty fathoms, the bottom being composed of 

 angular grains of fragments of coral and shells. Jukes was specially 



1 "The Great Barrier Reef of Australia, its Products and Potentialities." 

 London, 1893. 



2 Such as : " Im Australischen Busch und an den Kiisten des Korallenmeeres," 

 von Richard Semon. Leipzig, 1896, pp. 273, 345. " Der grosse australische Wall- 

 riff," von Albrecht Penck. Wien, 1896. 



3 Voyage of H. M. S. " Fly," Vol. I. p. 1. 



4 The Great Barrier Reef of Australia, p. 101. 

 6 Voyage of H. M. S. " Fly," Vol. I. p. 319. 



