8 A NATURALIST IN THE PACIFIC chap 



of coral-reef fragments in the volcanic agglomerates in any locality 

 examined, notwithstanding that these agglomerates are so 

 intimately associated with the fossiliferous tuffs and clays that their 

 submarine origin could not be doubted. 



The conditions for reef-formation evidently did not exist in 

 that early stage of the island's history, when the foraminiferous 

 tuffs and clays, now occurring at elevations of 2,000 feet and over, 

 were being deposited on the sea-bottom. At some time or other, 

 however, these high mountain-slopes, previous to their emergence 

 from the sea, must have been within the limits of the zone of reef- 

 building corals. If reefs had been formed along those ancient 

 coasts, or on the original shoals, they would have been in some 

 cases preserved, as in the case of the foraminiferous tuffs and clays, 

 by a covering of volcanic agglomerate. These soft submarine 

 deposits have been in this manner saved from the destructive effects 

 of denudation over a large part of the island whether on the higher 

 slopes or at the lower levels ; but no trace of reef-formation ever 

 came under my notice in the higher regions of the interior. This 

 is a puzzling point that will have to be considered in connection 

 with the origin of the great mountain ridges, one of the most difficult 

 problems in the history of the building-up of Vanua Levu. 



I will now refer to the evidence of the latest stage of the up- 

 heaval of the island as indicated at and near the sea-border by the 

 scantily occurring upraised reefs. The elevated reefs are mostly 

 to be found on the south coast between Fawn Harbour and Na 

 Viavia Islet off Harman's or Savu-savu Point. Na Viavia Islet 

 itself is 300 or 400 yards in length and is formed of much honey- 

 combed reef-limestone, which is raised 10 or 12 feet above the 

 high-water line. Proceeding eastward along the south coast of the 

 Savu-savu promontory we next come upon uplifted reefs in a 

 curiously isolated hill that rises on the coast between Naithekoro 

 and Naindi Bay. This hill is about 250 feet in height and is com- 

 posed in the mass of coral limestone. About 100 feet above the 

 sea-level it exhibits an erosion-line, above which it rises precipitously 

 to the summit. The west point of Naindi Bay is formed of reef- 

 limestone reaching to a height of 40 to 50 feet and displaying in 

 position massive corals, " Fungias," and " Tridacna " shells. Near 

 its base, four to five feet above the present high-water level, it 

 shows an erosion line. This limestone overlies a rock in which 

 blocks of volcanic rocks, five to six inches across, are imbedded in 

 a calcareous matrix. 



Raised coral limestone occurs at intervals on the coast between 



