Islands and Coral Reefs of Fiji. 411 



but merely suggested them as possibilities, and his critics may be 

 excused for giving their observations a relatively greater value than 

 to his theoretical views. 



" The whole argument of the great thickness of coral reefs based 

 upon the analogy of the so-called raised reefs of Cuba, described by 

 Professor Crosby and myself, or of the fossil reefs, is of little value, 

 as it has been pretty conclusively shown that these elevated reefs, 

 not only in Cuba but in the Pacific, are beds of Tertiary limestone 

 intercalated with beds of moderate thickness in which corals are 

 found, and the same is true of older fossil reefs. Furthermore, these 

 huge masses of Tertiary limestone w^hich form the substratum upon 

 vi'hich both in Cuba and in the Pacific recent corals have found 

 a footing, have played no part in the shaping of the barrier or 

 encircling reefs, or atolls, which, as we have attempted to show, owe 

 their origin in the main to mechanical causes. 



"Professor Bonney states that 'Much stress is laid upon the fact 

 that many coral islands afford evidences of a certain amount of 

 upheaval ; this amount, in most cases, is but slight, and its signifi- 

 cance appears to me to have been exaggerated ' ; and he considers 

 these indications to prove only oscillation. As far as the Fijis are 

 concerned, the elevation extended over the whole group, and has 

 been shown to amount to more than a thousand feet. In Australia 

 it extended along the whole east coast of Queensland for more than 

 a thousand miles, and was more than twenty-five hundred feet in 

 height ! He further says, ' If the coral reef be only a sort of cap 

 concealing a hill of pre-existent rock, we may reasonably be 

 surprised that the " ashlar rock " of coral limestone has in no case 

 so far yielded to the action of the atmospheric agencies as to lay 

 bare its inner support.' We can answer this point most decidedly. 

 In Florida the substratum underlying the recent coral reefs crops 

 out at many places, and the highest points of some of the Keys 

 consist of it. So do some of the hummocks in the southern part 

 of the Everglades near Key Biscayne. In the Bermudas the greater 

 part of the land of that group consists of the seolian rocks w^hich 

 underlie the recent coral reef. In the Bahamas the same is the 

 case, and along the northern coast of Cuba the Tertiary limestone 

 forming the substratum of the recent reefs crops out in all directions, 

 while in Australia rocks undeidying the Great Barrier Eeef can be 

 traced as islands, islets, or negro-heads all along its line for more 

 than a thousand miles. Finally, in the description of the islands of 

 Fiji this substratum appears over and over again, either composed 

 of volcanic rocks or of great Tertiary limestone banks. No better 

 example can be found of the appearance of the substratum of the 

 recent reefs than in Kaneohe Bay, Oahu, at the Sandwich Islands, 

 where the reef is studded with islets and negro-heads consisting of 

 volcanic rocks. 



" That corals grow in lagoons is well ascertained, and nowhere is 

 it better seen than in Fiji, where nearly all the islands enclosed by 

 barrier reefs are edged with, fringing coral reefs. But why that 

 should prevent a lagoon from being formed I cannot see. A lagoon 



