466 A CONTRIBUTION TO THE GEOLOGY OF VITI LEVU, FIJI, 



conglomerate occurs at Nukuilau, proving that granites were 

 exposed at the surface at the time when the bottom beds of the 

 tuffaceous series were being deposited. This tuffaceous series 

 reaches a thickness of at least a couple of thousand feet, and is 

 level-bedded and almost certainly marine. It is probable that 

 the cave limestone of Tawaleka is part of this series, though it 

 is by no means impossible that it may be portion of an older 

 series. There are beds of tuff (?) east of Natuatuacoko, dipping 

 W.N. W. at high angles; their relationship to the limestones and 

 granites remains to be discovered. The upper portion of Muani- 

 vatu consists of an enormous mass of pyroxene andesite. 



X. — Navosa Plateau. 



This district lies at a very uniform height of 3,000 to 3,500 feet 

 above sea-level. It stretches from the Wainimala on the east, to 

 the Sigatoka on the west. Southwards it is bounded by the deep 

 valleys south of Muanivatu and Korolevaleva. Northwards it 

 runs into the higher portion of the Nadarivatu Plateau, which 

 culminates in Toma na Ivi at 4,555 feet. 



Both east and west slopes are extremely steep. As noted 

 above (p. 458), a considerable river plunges over its eastern 

 scarp, and forms the magnificent falls of Wavou, near 

 Waibasaga on the Wainimala. Throughout the greater part of 

 its extent it consists of level-bedded soapstones which, for reasons 

 given above, I consider to be of marine origin. Only in the 

 lower portions of its eastern scarp are solid rocks met with. 

 Here there are pyroxene andesites resting on granite. Its 

 western scarp, forming the left bank of the Sigatoka gorge at 

 Namoli, is composed of soft, greasy, level-bedded "soapstone" 

 almost down to river-level. Only at tv/o points on the surface 

 of the plateau were solid rocks encountered, and these were 

 certainly parts of the Muanivatu mass just described. Almost 

 the whole surface is a hideous morass.* It is drained (!) by 



* I strongly advise anyone intending to cross this plateau to do so either 

 from Nadrau to Rewasau, or from Naduta to Nasava, via Korolevaleva. 

 These tracks are both bad, but nothing like so bad as the dreadful one from 

 Namoli (or Tavua) on the Sigatoka to Waibasaga on the Wainimala, 



