VII SOLOA LEVU 105 



this change. On page 312 will be found a description of the basic 

 glass of these agglomerates in its fresh and in its altered condition. 

 Huge blocks of these rocks strew the surface on the south-west 

 slopes of Soloa Levu, and in one place the underlying acid andesite 

 that forms the mass of the hill is exposed in a stream-course. 



These pitchstone-agglomerates and palagonitic pitchstone-tuffs 

 are elevated between 600 and 750 feet above the sea. As one 

 proceeds on the road to Vunivuvundi and skirts the south-east side 

 of the hill one ascends the western border of the basaltic Wainunu 

 table-land which, however, is much cut up by rivers in this locality. 

 Here the tuffs and agglomerates give place to a basaltic andesite, 

 and on reaching an elevation of 1,000 feet we arrive at the top of 

 the table-land from which an ascent of Soloa Levu is easily made. 

 The road then lies on, but parallel to, the border of this plateau for 

 some distance until it descends into a deep valley worn by one of 

 the tributaries of the Wainunu River. 



This hill of Soloa Levu is in fact a mass of acid andesite 

 situated in the midst of an area of basic rocks. I found basaltic 

 rocks exposed in the stream courses to the north and similar rocks 

 prevail on the north-west on the way between Nambuna and 

 Tambu-lotu. It has been above remarked that on the east and 

 south it has been in part surrounded by the basaltic flows of the 

 Wainunu table-land, and that pitchstone-tuffs and agglomerates 

 cover its lower slopes on the west and south-west, yet it is not easy 

 to find any trace of the vent from which they flowed or were 

 ejected. 



It may be here remarked that the occurrence here and there 

 of basic rocks in the midst of this region suggests the vicinity of 

 dykes. For instance, in a deep gulley about half a mile south-west 

 of Kalakala, where a dacitic rock was exposed in sitUy I came 

 upon a single large mass of an aphaniticaugite-andesiteof the type 

 described under genus 16, species A, of the augite-andesites. 



The Altered Acid Andesites of the Ndrandramea 

 District. — One of the most important features of the geological 

 structure of this district lies in the fact that the bed-rock exposed 

 in the lower region between the hills is a highly altered acid 

 andesite of the type found in the hills around. By referring to the 

 map of this locality, it will be observed that between the Ndrand- 

 ramea hills on the west and the Ngaingai hills on the east is the 

 valley of the Tambu-lotu river and its tributaries, an open broken 

 country deeply eroded by the streams, and elevated 600 to 700 feet 

 above the sea. These altered rocks are well exposed in the deep 



