BY W. G. WOOLNOUGH. 469 



at this point contain numerous large pebbles of granite and 

 diorite, particularly the latter. 



About 3 miles above Naseuvou is the village of Delai Lasakau, 

 situated at the junction of a fairly large affluent, the Wainivadu, 

 with the main stream. This affluent contains subangular boulders 

 of diorite several feet in diameter, so that it may safely be 

 inferred that the diorite occurs in situ at some distance up the 

 stream, which drains the countr}^ immediately to the east of 

 Korobasabasaga. Owing to the swollen condition of the torrent, 

 I was unable to locate the diorite in situ at this locality. 



A subtributary entering the Wainivadu from the east contains 

 only andesite p6bbles derived from exceedingly solid sheets of 

 that rock. This to some extent limits the area from which the 

 diorite may have been derived. 



In tlie gravels of the Waidina, above its junction with the 

 AVainivadu, plutonic rocks are absent, so that no exposure of 

 such rocks can exist anywhere in the area drained by the upper 

 AVaidina. Three miles above Delai Lasakau the hills close in 

 round the river. They are composed almost entirely of andesite 

 agglomerate and rise to heights of 500 to 700 feet (estimated) 

 above the river. 



From the village of Nailielie a good view is obtained of a range 

 of hills extending in an almost unbroken line for 90° of the 

 horizon. The outlines of these are very suggestive of the denuded 

 remnants of a line of volcanic centres, as the photographs show 

 (Plates xxv.-xxvi., figs. 7-8). The valley just at this point is con- 

 siderably wider than usual. The trend of this line of hills is 

 roughly N.W. and S.E. 



After leaving this piece of open valley the river again enters 

 the hills, and they continue right up to the source, the valley 

 becoming simply a gorge never more than about one mile wide, 

 often much less, bounded by perpendicular cliffs ivdiich in some 

 cases rise to a height of fully 1500 feet (estimated). The rocks 

 composing these cliffs are mostly enormously solid and coarse 

 andesite agglomerate, the boulders being 3 to 4 feet in length. 

 With these agglomerates are associated solid andesites. Some 

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