294 A NATURALIST IN THE PACIFIC chap. 



Viti Levu, Kandavu, Mbenga, Totoya, Malolo, Yasavva 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 someaugite. Mr. E. C. Andrews 1 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, 2 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, 3 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." 



1 Notes on the Limestones and General Geology of the Fiji Islands, Bull. 

 Mus. Comp. Zool , vol. 5. Geolog. Ser. vol 5, no. 1, Cambridge, Mass., U.S.A. 

 Nov. 1900. 



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

 Ovalau. 



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



