EAKLE. — IIUCKS FROM THE FIJI ISLANDS. 593 



were collected from the top of the ridge, and from the interior of the 

 bowl. 



The specimen from the top of the ridge is somewhat decomposed, but 

 resembles the basalt from Wakaya. 



The groundmass has a pilotaxitic structure consisting of rather long 

 parallel arranged laths of feldspar and a speckled mixture of augite and 

 feldspar niicrolites with magnetite and olivine grains. The phenocrysts 

 are labradorite, augite, and olivine. 



The rock contains very few large sections of feldspar, most of this 

 constituent appearing as slender laths in the groundmass. 



Augite occurs in very large pale green crystals, which are usually 

 much broken up and of irregular form. Zonal structure is well shown. 

 Some of the sections contain areas of rectangular-shajied glass inclusions. 

 These are also seen in the larger feldspar sections. 



Olivine is scattered throughout the rock in small corroded grains, with 

 a few fragments of larger phenocrysts. It is all coated reddish brown. 

 From the characteristic yellowish to reddish brown grains in many of 

 these rocks, iddingsite is strongly suggested ; yet the coloring matter is 

 in general not homogeneous throughout the grain, the centres often being 

 colorless and showing the high polarization colors of olivine. 



Calcite fills several of the cavities as a secondary formation, and usu- 

 ally has a brown border from the presence of much iron oxi<le. This 

 oxide of iron, which has apparently arisen through the alteration of the 

 olivine, has filled many of the cavities with the same banded layers as 

 previously noted. 



The specimen from the interior of the crater has an orthophyric type 

 of groundmass, and the rock is a basaltic lava. 



Short rectangular and square sections of feldspar are numerous, be- 

 tween which is a dusty brown glass. No original dark silicate is present, 

 but secondary serpentine is common and in many cases fills the cavities 

 with light yellowish green radiating fibrous bands. Brown limonite is 

 also a frequent filling for these cavities. Large areas of calcite and a 

 few cavities having quartz in them occur. 



Olivine Andesite from Kambara. 



Kambara is the next island visited, just east of Totoya. It is one of 

 the southern islands of the Lau or Eastern group, and is four and a half 

 miles long by three miles broad. 



The hand specimen shows a very fine dark gray holocrystalline rock, 

 with no porphyritic structure apparent. 

 VOL. XXXIV. — G8 



