156 A NATURALIST IN THE PACIFIC chap. 



in lofty cliffs 400 or 500 feet in height. At their base, which is 

 about 1,000 feet above the sea, once stood the village of Lovutu. 

 These cliffs are formed of basic agglomerate-tuffs which display a 

 horizontal arrangement, but there is no distinct bedding. They 

 have the castellated appearance that often characterises horizontally 

 bedded sedimentary formations. The inclosed rock-fragments 

 vary in size from 18 inches to half an inch and smaller. The 

 larger are angular or sub-angular, and are composed of hemi- 

 crystalline basaltic andesites, scoriaceous and vesicular and some- 

 times amygdaloidal. The smaller fragments are more or less 

 rounded and of the same material. The matrix is made up of fine 

 detritus of the large fragments and of lapilli of a vacuolar palagonitic 

 basic glass, whilst small crystals of calcite fill the cavities and line 

 the fissures. The phenocrysts of plagioclase and augite inclosed 

 in the altered glass also display extensive alteration, and in the 

 first case are largely replaced by calcite, secondary quartz, and 

 other products. No organic remains came under my notice ; but 

 on account of the alteration of the tuff-matrix their preservation 

 could hardly be expected. Bearing in mind, however, the fossili- 

 ferous character of the tuffs and agglomerates in the higher part 

 of the range, it can scarcely be doubted that the agglomerate-tuffs 

 of the Sealevu cliffs are also submarine. 



Each traverse of the great Koro-tini Range will provide us with 

 new facts to aid us in framing an explanation of the origin of this 

 long mountain-ridge. The principal lesson to be learned from the 

 journey across the range from Waisali to Sealevu, and from the 

 visit to the cliffs, is concerned with the great extent and thickness of 

 these submarine basic tuffs and agglomerates. From 1,000 feet 

 above the sea up to the summit, 2,400 feet in height, they are 

 almost the only rocks exposed, excepting the occasional masses of 

 basaltic rocks, which probably represent dykes. Their maximum 

 thickness must amount to some hundreds of feet. 



(2) Traverse of the Koro-tini Range from Mbale- 

 MBALE TO Vandrani. — In this traverse the track before as- 

 cending to the summit crosses a spur of the Koro-tini Bluff, and 

 then descends into the valley of the Natoarau river on the east 

 side of it. It will therefore be convenient to describe the bluff 

 before giving my description of the journey across the range. 



The Koro-tini Bluff is a lofty headland (if I may so term it), 

 lying about four miles inland from the mouth of the Ndreke-ni-wai. 

 It attains an elevation of about 2,000 feet, and terminates above 

 in a line of precipices 300 or 400 feet in height. It i-epresents the 



