cH. I LEADING PHYSICAL FEATURES 5 



range, composed mainly of grey olivine-basalts, which is not 

 indicated in the profile. 



The two conical peaks of Vatu Kaisia (i, 880 feet) and Na Raro 

 (2,420 feet), which rise up so unexpectedly in the region imme- 

 diately east of the Ndrandramea district, are also of acid andesitic 

 locks, in the last case approaching the dacitic type. They lie 

 ^vithin the borders of the area of basic tuffs, basic agglomerates, 

 and basic massive rocks, that here begins and extends eastward 

 10 Mount Thurston and a little beyond. East of Na Raro there 

 is a gap or break in the profile, where the greatest elevation is 

 ] )robably not over 800 feet ; and on its farther side rises up the 

 mountain of Va Lili (2,930 feet), a lofty inland ridge that lies 

 towards the southern coast. Palagonite-tufifs and agglomerates are 

 the prevailing surface-formations in this district. 



Eastwards from Va Lili extends for eight or nine miles a lofty, 



level-topped, and almost peakless range, which I have called the 



;^orotini Table-land, after the towns once situated on its southern 



; lopes. Its outline is shown in the background of the view facing 



)age 153. It is, however, not so level-topped as it appears to be; 



)ut the gradual variations in elevation between 2,000 and 3,000 feet, 



vhen spread over a length of some miles, are more or less lost in 



he general outline of the range as viewed from the coast. Basic 



agglomerates are principally exposed on the lower slopes; whilst 



liigher up, reaching often to the summit of the table-land, occur 



j)alagonite-tuffs containing tests of foraminifera and molluscan 



! hells, massive basic rocks being exposed in places. 



The level profile of the Korotini tableland gives place, as one 



)roceeds eastward, to the broken outline of the several lofty peaks 



of Mariko (2,890 feet), Mbatini (3,437 feet), Thambeyu (3,124 feet) 



■ md others.^ Each of these peaks marks one of the bold 



nountain-ridges that form such a striking feature in the surface- 



I onfiguration of this part of the island. On the slopes of these 



: idges, and often also on their summits, appear basic agglomerates 



; .nd palagonitic tuffs and clays often inclosing tests of foraminifera ; 



' i^hilst exposed in the gorges and protruding at times through the tuffs 



; .nd agglomerates on the crests of the ridges are displayed massive 



)asic rocks of the type of the hypersthene-augite andesites. 



East of Thambeyu the level sinks to about 1,000 feet above 



1 Mariko is the native name ot the Drayton Peak of the chart. Mbatini 

 i i the correct name for the Koro Mbasanga of the chart, the true Koro 

 : Ibasanga lying three miles to the north. Thambeyu is a native name for the 

 ; lount Thurston Range. 



