BY W. G. WOOLNOUGH. 467 



a, number of streams of fairly considerable volume. Towards its 

 south-west corner these streams flow into the Sigatoka, but 

 throughout the greater part of its extent the drainage is towards 

 the Wainimala. Thus the Sigatoka, along part of its course at all 

 events, like the Navua and Rewa, keeps close to the eastern 

 margin of its watershed. The apparent exceptions to this 

 general rule are almost certainly due to piracy of Wainimala 

 water by branches of the Sigatoka in the Muanivatu area. 



The plateau, though rather barren geologically, is an extremely 

 important topographic feature. It has a powerful effect upon 

 climate and rainfall, and on the distribution of the flora of the 

 island. To the east, we have the heavily forested country and 

 bamboo jungles of the Rewa and its tributaries; to the west, the 

 rolling hills of the Sigatoka and Ba, covered with a jungle of 

 reeds about 8 to 10 feet high. The surface of the plateau is 

 densely wooded, but the downward limit of forest trees on the 

 western side is extremely sharply defined, and forms a most 

 remarkable *' timber line." It has also had a powerful influence 

 on the migration of the Fijian tribes; the people on opposite sides 

 of the range belong to quite distinct types. 



Summary of Section x. — The Navosa Plateau 

 separates the Wainimala and Sigatoka Valleys, and rises to an 

 average height of over 3,000 feet above sea-level. On both east 

 and west it is bounded by steep escarpments. It is almost 

 entirely composed of level-bedded soapstones, which on the 

 eastern side overlie, and on the western underlie, andesitic rocks. 

 Below the falls of Wavou on the east, the andesites overlie the 

 granitic rocks of the Narokorokoj^awa series. It is an extremel}'' 

 important feature in determining the distribution of climate, 

 rainfall, vegetation, and races of men. 



xi. — Nad rau-Reivasau Section. 



This belongs structurally to the Navosa Plateau, but I have 

 separated it to call special attention to two very important 

 occurrences. One is the section at Nadrau on the Sigatoka, the 

 other that at Rewasau, in the Wailoa Valley. 



