/ SOLEVU BAY 77 



iecond rock to be noticed is a slightly altered compact basalt 

 without olivine forming apparently a dyke near the coast about 

 lalf way between the village of Solevu and Ua-nguru Point. It 

 ;ias a specific gravity of 2*84, the felspar lathes ("15 mm.) presenting 

 .1 marked flow-arrangement, whilst there is a fair amount of altered 

 •esidual glass in irregular spaces, a millimetre in size. The rock, on 

 account of its joint-structure, could be easily worked as a building- 

 stone. It is referred to genus 16, species B, of the augite andesites. 

 The hill of Koro-i-rea, which rises on the east side of the bay 

 I0 a height of 850 feet, has a ridge-shaped summit. Its upper 

 half is composed of a bluish-grey rock looking like a phonolite and 

 usually compact, except at the top of the hill, where it is a little 

 i coriaceous. It has, however, a specific gravity of 2'gi or 2*92, 

 f.nd is in fact a pretty grey olivine- basalt studded with small 

 C'livine crystals about a millimetre in size and showing no other 

 phenocrysts. This type of olivine-basalt occurs also at Ulu-i- 

 iidali on the east side of Wainunu Bay, but is rare in the island. 

 It differs amongst other features from the porphyritic olivine- 

 l asalts of the northern part of Seatura and of the Seatovo range 

 i 1 the absence of plagioclase phenocrysts. There is apparently no 

 iiterstitial glass, whilst the average length of the more or less 

 ( arallel felspar-lathes is '13 mm.^ On the lower slopes of the hill 

 tie common blackish porphyritic basalt or basaltic andesite is 

 exposed. In the grey-basaltic upper portion of this hill we have 

 I robably an old volcanic " neck." 



Following the line of hills inland from Koro-i-rea, we cross the 

 i itervening saddle 450 feet above the sea, and ascend the slopes of 

 1 loro-tolutolu, a ridge-shaped mountain backing Solevu Bay, and 

 h aving, as its name indicates, three peaks, of which the highest is 

 1 ,280 feet above the sea. My observations indicate that this moun- 

 t lin is formed in mass of the common blackish-basalts described 

 t nder genus 37, their specific gravity being 2*88 to 2*94. But Koro- 

 t )lutolu has also the peculiarity that it appears to be in mass 

 r lagnetic. The rocks obtained from its summit, half-way up its 

 V estern slopes, and near its foot on the same side, all display 

 f Dlarity, a character also of the rocks of the neighbouring hills of 

 I lu-i-matua and Koro-i-rea, but in their cases seemingly confined 

 h > the higher levels.^ 



Neither tuffs nor agglomerates came under my notice at Solevu 

 I: ay. This appears to be an ancient corner of the island, from 



* Referred to genus 16 of the olivine-basalts. 

 ' This subject is discussed in Chapter XXVI. 



