472 THE CONTINENTAL ORIGIN OF FIJI, 



Some distance above this point tlie bank of the stream shows a 

 solid section of much jointed mehiphyre, which continues for a 

 considerable distance. 



Just below the town of Qarawai there is a mass of amygdaloidal 

 melapln're with a decidedh' greenish colour in mass. This rock 

 contains well developed natrolite. Other outcrops of the same 

 character can be seen on the other side of the town. These rocks 

 and the preceding ones, which are almost certain, from lithological 

 characters, to be lavas, have a distinctly ancient appearance as 

 compared with an}^ met with up to this point, except the diorite 

 at Nasirotou. They are highly jointed, which the common 

 andesites are not, with the exceiDtion of one at the junction of 

 the Navua and the Waimala near Korowaiwai, They are of 

 very different mineralogical constitution, and they are much more 

 highl}^ acted on by atmospheric agencies, with formation of 

 greenish decomposition products. No actual junction was 

 observed, but it is probable that the beautifully fresh andesites 

 lie on a denuded surface of which these jointed lavas (?) form a 

 part. I feel sure that they are older* than the andesites and 

 associated rocks. 



The town of Nasau is situated at the junction of the main river 

 with an affluent, the Wainibua. The former stream comes down 

 from the north-west, and carries boulders consisting almost 

 entirely of quartziferous diorite, though the quartz is only inter- 

 stitial. The gravels of the Wainibua also consist of quartz 

 diorite, but the quartz is more apparent macroscopicall}^ 



At the village of Wainiveidro the quartz diorite or hornblendic 

 granite is certainly in situ, though the sections are not very good. 

 From the above-mentioned village an excursion was made to the 

 summit of KoroVjasabasaga. There is no track, but we followed 

 up one of the leading spurs to the saddle joining the southernmost 

 and lowest of the five great summits with the next to the north. 



* The Section (Plate xxxiv.) shows that their point of outcrop is exactly on 

 the slope joining Navunitorilau, Nadranikula, Wai ni Vadu and Nasirotou, 

 at all of which crystalline rocks occur. 



