294 A NATURALIST IN THE PACIFIC chap. 



Viti Levu, Kandavu, Mbenga, Totoya, Malolo, Yasawa group, and 

 in several other small islands, he inferred that the hornblende- 

 andesites are much more limited in their occurrence in Fiji than the 

 augite-andesites ; whilst hypersthene-andesite was only represented 

 in the collection from Vomo-lailai near Waia in the Yasawas. The 

 specimens from Waia had a microfelsitic base with pseudomorphs 

 of hornblende and some augite. Mr. E. C. Andrews ^ in his account 

 of his collection of volcanic rocks, made mostly in the Lau Group 

 and Taviuni, makes no special reference to hornblende-andesites, 

 the andesites being mainly augitic, rhombic pyroxene also occurring 

 as a common porphyritic constituent. 



It may be inferred from the above and from my own observa- 

 tions in Vanua Levu below given that hornblende-andesites have a 

 relatively limited distribution in Fiji. They are not generally 

 distributed as in the case of the augitic and basaltic andesites ; but 

 are confined to certain localities in Viti Levu,^ Vanua Levu, Ovalau, 

 Kandavu, Ono, Malolo, Yasawa Islands, etc. 



The occurrence of quartz-andesites or dacites in Fiji. — In con- 

 nection with the existence of these rocks in Vanua Levu, it is note- 

 worthy that except in Mr. Eakle's paper there is no reference in any 

 of these writings to the occurrence of quartz-andesites in Fiji. 

 Wichmann expressly states that the rocks he examined were free 

 from quartz, and that up to his time (1882) no quartz-bearing 

 younger eruptive rocks were known from the South Seas. Mr. 

 Eakle in 1899 described a holo-crystalline andesite with a felsitic 

 aspect from Malolo and another similar looking rock from Vatu 

 Mbulo, in the same sub-group of the Fijian Islands, showing quartz 

 both in the phenocrysts and in the microcrystalline groundmass, 

 concerning which he observed that it was perhaps more of a dacite 

 than an andesite. Dacites were found by me in 1884 in the island 

 of Fauro in the Solomon group,' and it is probable that they are of 

 more frequent occurrence in the Pacific than has been generally 

 supposed. As shown immediately below, they are represented in 

 Vanua Levu ; and the extent of their distribution in the island 

 depends on the limits we assign to the definition of the term 

 " dacite." 



' Notes on the Limestones and Geiieral Geology of the Fiji Islands, Bull. 

 Mus. Comp. Zool , vol. 5. Geolog. Ser. vol 5, no. i, Cambridge, Mass., U.S.A. 

 Nov. 1900. 



^ Wichmann describes rocks from the cliffs of the Singatoka river and from 

 Ovalau. 



^ Geology of the Solomon Islands, by H. B. Guppy, 1887, pp. 6, 36. 



