422 THE GEOLOGY OF THE NEW HEBRIDES, 



Extending continuously down the west coast is a high range 

 of mountains attaining a maximum elevation in Losubunu, 

 5520 ft. (Plate xviii.). These mountains ascend steeply from the 

 sea, rising in a succession of sharp ridges culminating in lofty 

 peaks onl}^ four to six miles inland. The eastern flanks are much 

 less precipitous; after descending to 4000 ft., what appears to be a 

 plain of marine erosion, deeply furrowed by short and rapid rivers, 

 is a noticeable feature extending along the range for quite 10 miles, 

 surrounding the peak which rises high above it as a monadnock. 

 Beyond as far as the east coast, a distance of 20 miles, the high 

 lands of the interior continue to maintain their plateau-like 

 aspect, though with decrease in altitude, and occasional inter- 

 ruption by minor features (Plate xxi.) On the east coast, where 

 the plateau was ascertained to be built of recent raised coral 

 and reef debris, it is only 500 or 600 ft. in height, and is 

 noticeably more elevated in the north than in the south. This 

 agrees with the evidence obtained in Malekula indicating a general 

 dip to the east in conjunction with a less noticeable sag in 

 towards the nearest volcanoes. 



On the south and east numerous small islands line the coast, 

 and are found to maintain the same general geological features 

 with the adjacent mainland. Along the west coast recent raised 

 reef-material is little represented further north than C. Ukuani 

 (Plate XX.). Beyond that point older rocks, amongst which is a 

 highly-tilted Miocene series similar to that already described 

 from Malekula, outcrop at sea-level (Plate xvii.), and rising 

 steeply appear to compose, with related andesites, the whole mass 

 of the neighbouring elevated ridges. 



Above the Miocene, and developed most strongly on the 

 eastern side of the island, come soft submarine tuffs of the Fiji 

 soapstone type, capped above by a variable thickness of recent 

 raised coral attaining a maximum observed elevation of about 

 1000 ft. 



It is to be noted that the fine-grained grey gneiss reported by 

 M. Levat as being eminently characteristic amongst the rocks of 

 West Santo and West Malekula, was not met with by us; the 



