76 A NATURALIST IN THE PACIFIC chap. 



a continuation inland of the eastern arm of the bay, and joins the 

 Seatovo Range at the head of it. Between these two ranges in- 

 closing the bay lies the valley of Solevu, down which descends the 

 Solevu River to the sea. In ascending this valley from the shore, 

 one rises only about lOO feet above the sea for the first mile or two. 



The promontory, which in the even-topped Ulu-i-matua or 

 Solevu Peak, attains a height of i,ioo feet above the sea, displays 

 on its summit and on its eastern slopes descending to the Solevu 

 river, and on its western slopes reaching down to the coast at 

 Vuia, more or less porphyritic blackish olivine-basalts of the usual 

 type with specific gravity 2"88 — 2'go. These basaltic rocks 

 contain scanty olivine and only a little interstitial glass. The 

 felspars of the groundmass vary in different localities from "ii 

 to •15 mm. in average length. The rocks belong to genus 37 of 

 the olivine class which is described on page 262. 



They are in the lower regions often decomposed to a consider- 

 able depth, the spheroidal structure being well displayed during 

 the weathering process. Where this promontory terminates in the 

 low Vulavulandre point, these rocks give place in part to grey 

 porphyritic olivine-basalts, with specific gravity 279 — 2*83, which 

 from the abundance of the macroscopic opaque felspar look like 

 porphyrites. They come near to the rocks exposed on the north 

 slopes of Seatura and in the Seatovo Range. At the end of the 

 point they become scoriaceous and more vitreous ; but with this 

 exception they contain but little glass. They vary somewhat in 

 character and are referred to genera 2 and 38 of the olivine-class. 



The prevailing rock in the interior of the Ua-nguru pro- 

 montory to the south of Koro-i-rea is the blackish porphyritic 

 basalt, containing a little olivine, and often much decomposed ; but 

 at the point and on the east shores of Solevu Bay, there is a con- 

 siderable variation in the character of the basic rocks, of which the 

 two following are the most conspicuous. Near the village of 

 Nawaindo, there is an apparent intrusion of a black lava-like basalt 

 of high basicity (specific gravity 3*01) showing abundant large 

 olivine crystals, five or six mm. across, with some porphyritic 

 augite, but no macroscopic felspar. At the point the rock is 

 somewhat scoriaceous, with calcite occasionally filling the cavities, 

 whilst the olivine is so thoroughly haematised that it glistens like 

 brown mica. The compact rock contains a little devitrified inter- 

 stitial glass, the felspar-lathes being unusually small, their average 

 length being only "07 mm. It belongs to genus 15, the most basic 

 of the genera of the olivine class represented in the island. The 



