GEOLOGICAL OU^^EUVATIONS L\ FIJI. 107 



Its position in tlic norm chissification is, thcrcrore: — 



Class 1 IVrsiilanc 



Order 4 Britannare 



Rang 3 ( 'oloradasc 



Subrang 4 Ycllowstonose. 



Of the rocks classificMl by Washington (1908, pg. 101) nnder this 

 system, a c[nart/--(liorite from Ariiba Island, West Indies is most 

 closely allied to the Fiji type. 



2). Diorific (Jahliro. Immediately back of the village of Wai- 

 mbasanga low, rounded hills of gabbro rise to heights of 75 to 100 feet 

 abo\e the level of the Singatoka river. The relation of the gabbro 

 to the granite is not exactly known. As one passes further south the 

 gabbro disappears and diorites and granites outcrop. The textural 

 similarity of these rocks leads to the belief that they are transitional 

 into one another. 



A Kosiwal measurement of the rock gave the following r(>sult. 



Labradorite 62 . 85 per cent 



Amphibole 27.90 " " 



Magnetite 9.01 " " 



Titanite .2A " " 



100.00 " " 



The feldspar shows pericline and albite twinning. It is zoned and 

 has a composition varying from AbsoAnso to Ab4oAnco. 



The amphibole is uralitie, probably derived from pyroxene, though 

 none of the latter mineral remains. It is sometimes in crystals of 

 considerable size but more often forms a felted mass of minute shreds. 

 The rock is very fresh in appearance and has a hypidiomorphic, 

 granular structure. Its order of crystallization was probably as fol- 

 lows : — 



titanite, 



magnetite, 



augite, 



feldspar, 



amphibole. 



3). Aporhijolite or Quartz porpJnjri/. Aporhyolites were not found 

 in place in Viti Levu. The rocks to be described occur as pebbles and 

 boulders in the conglomerate described from the Visari river, near 

 Suva. 



