xiv THE WAIKAWA MOUNTAINS 201 



Lea and Waikawa mountain-ranges. In the lower part of the 

 northern slopes of this ridge occur basic tuffs and agglomerates ; 

 but between 200 and 400 feet a light-coloured acid rock of the 

 hornblende-andesite type prevails, both in the form of agglomerate 

 and of loose blocks. This rock is described under the second 

 order of the hornblende-hypersthene andesites on page 299. 



Descending the south slope, I found at an elevation of 500 

 feet a single large mass, about 4 feet across, of quite another type 

 of volcanic rock, which is referred to the orthophyric order of the 

 hypersthene-augite andesites (page 290). It is a dark grey almost 

 holo-crystalline rock (sp. gr. 2'69) showing porphyritic pyroxene to 

 the eye and displaying in its relatively scanty groundmass short 

 stout felspars, '05 mm. in length. On the surface of the lower 

 two-thirds of this southern slope occur basic tuffs and agglo- 

 merates, basaltic blocks being found in the streams. The tuffs 

 are palagonitic and contain a few calcareous particles. They 

 apparently contain some foraminiferous shells and are doubtless of 

 submarine origin. 



It would seem that the axis or deeper portion of this ridge is 

 composed of the hornblende and hypersthene-augite andesites, 

 whilst the basic tuffs and agglomerates form the slopes. 



With reference to the south side of the Lea sub-district, it 

 may be observed that whilst on the north side the mountains rise 

 up close to the sea-border, here they are separated from the coast 

 by a broad tract of lowland, where bedded pteropod and foramini- 

 ferous clay-rocks are exposed, dipping gently to the south-east. 

 Usually between Fawn Harbour and Vunilangi Inlet the coast 

 is margined by low cliffs of coral-limestone, showing the massive 

 corals in position ; but sometimes the deposits above noticed 

 compose the low cliffs and even the islets close by. 



The Waikawa Mountains. — This range occupies nearly the 

 whole area of the broad and elevated promontory that is only 

 separated from Taviuni by the narrow straits of Somo-somo, 

 which, however, have a minimum depth of 120 fathoms. These 

 mountains extend to the vicinity of Mbutha Bay on one side and 

 to near Fawn Harbour on the other. Several of the peaks reach 

 to over 1,000 feet, the greatest height given in the Admiralty 

 chart being 1,540 feet. The whole region has a very rugged 

 aspect, the mountains rising up near the coast, whilst the surface is 

 much cut up into ridges and valleys. 



A single traverse across the range was alone made, but the 

 results obtained are very suggestive and may doubtless be applied 



