212 A NATURALIST IN THE PACIFIC chap. 



to be assumed that there existed originally a line of submarine 

 vents, some of them ejecting acid and others basic materials. 

 Mainly on account of the great marine erosion during the period 

 of emergence, but partly also on account of the subsequent sub- 

 aerial denudation, a plain ridge now represents this line of vents. 

 Probably the peak of Uthulanga, which is evidently an old 

 volcanic neck, represents the last of the stages in the volcanic 

 history of this ridge ; but a very long period must have since 

 elapsed. When, however, we look at the exposed gabbro at the 

 other end of the ridge, we have to carry the period much farther 

 back, since here the superjacent surface volcanic rocks have been 

 stripped off completely. On page 2 I have referred to an island 

 in the Solomon Group where we have such a chain of ancient 

 vents of acid and basic rocks. In that case the forms of the 

 separate hills indicating the original vents are still to be recog- 

 nised. In this old mountain-ridge of Vanua Levu no such outlines 

 remain except in the instance of the terminal peak. 



(b) The Nailotha and Vungalei Range.— T^ixs lofty range, 

 which towers above all around it, attains a height of 2,481 feet 

 in the peak of Nailotha and of 2,238 feet in that of Ndrukau 

 or Vungalei. The first is, as I infer, the Ndoendamu or Hale 

 Peak of the charts ; but it is uncertain whether the name Savu-riti 

 should be applied to the northern peak of the range as it is in 

 the charts, or whether it belongs to an independent peak farther 

 to the east. By the natives in the vicinity the northern peak is 

 known as Ndrukau, and I have added the name of Vungalei 

 from the village at its foot. The southern peak is that of 

 Nailotha. The range runs roughly north and south. It is, how- 

 ever, obvious that the internal topography of this part of the island 

 is but scantily known. 



Brief reference will first be made to the country bordering the 

 range on the north-west and west sides in the vicinity of the 

 villages of Vungalei and Tembe. In proceeding south from 

 Kalikoso, which lies in the midst of the low-lying Wainikoro 

 plains, to Vungale one traverses this level district, of which the 

 elevation is never more than 150 feet above the sea and often 

 much less. About a mile south-east of Kalikoso the limit of the 

 region of quartz-porphyries and of acid tuffs is passed and the 

 area of basic rocks is entered, a dark semi-vitreous pyroxene- 

 andesite with a flinty fracture prevailing at the surface as far 

 as Vungalei. This rock displays a few small phenocrysts of oligo- 

 clase and pyroxenes in a blurred glassy groundmass exhibiting 



