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 fragments 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 foraminifera 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 palagonite-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.