XI 



THE KOROTINI RANGE 161 



The summit of the range may be described as a " ridgy " table- 

 land. Though about 2 miles in breadth, its level only varies 

 between 2,000 and 2,200 feet, the inequalities being probably the 

 effect of denudation. Here, as in many other similar localities, on 

 account of the dense forest it was only possible to determine the 

 surface-configuration by the use of compass, watch and aneroid. 

 The prevailing rocks displayed in this region are grey non-calcareous 

 basic tuffs, somewhat altered in character, and composed of frag- 

 ments usually not exceeding 1 mm. in size of a basic glass, the 

 palagonitic process being masked by other changes. These tuffs 

 often become brownish-yellow through hydration. Tests of foramin- 

 ifera are enclosed, but they are very scanty. 



On the north slopes basic agglomerates and palagonite-tuffs are 

 the predominant rocks down to the foot of the range. A specimen 

 of the tuffs taken at 1,300 feet is calcareous in patches and probably 

 contains tests of foraminifera ; but it is too much weathered to 

 enable one to speak with certainty on this point. The interesting 

 feature of this slope is the exposure at 1,600 to 1,700 feet of large 

 blocks of a dark grey hypersthene-augite andesite referred to the 

 orthophyric order of those rocks described on page 290. Lower 

 down (1,000 — 1,300 feet) occasional solitary blocks of the same rock, 

 but somewhat altered, occur imbedded in the pal agon ite-tuff. This 

 type of rock which is characterised by the orthophyric structure of 

 the groundmass and by other features is rarely represented in 

 Vanua Levu. 



Summing up the general results of this traverse we observe that 

 here, as in other parts of the range, basic agglomerates, breccias, 

 and tuffs, the last however scantily foraminiferous, occupy a great 

 extent of the slopes and summit. The alteration of these deposits 

 on the southern slopes is noteworthy. The only deeper seated 

 massive rocks observed were the pyroxene-andesites above alluded to. 

 (4) Traverse of the Koro-tini Range from Nukumbolo 

 TO SUENI. — The hot springs at Nukumbolo, which are described 

 on page 24, rise up through agglomerate-tuffs. Around the 

 bathing pools lie large masses of altered palagonite-tuffs which give 

 the first indication of the region of altered rocks that extends from 

 Nukumbolo to the lower slopes of the range, a distance of about 

 three miles. 



For about a mile and a half or two miles from this place the 

 track lies through a broken country and does not rise to a height 

 more than 300 feet above the sea. A variety of altered rocks are 

 here exposed in position in the stream courses. Some of them are 



M 



