NORTH MELANESIA. 



321 



yet been determined. The Admiralty Archipelago consists mainly of coralline 

 rocks, and here a mass, 2,970 feet high, occupying the centre of the large island 

 of Taui, is alone said to be of plutonic origin. 



Among the less elevated hills in New Hanover, Tombara (New Ireland), and 



Fig. 138.' White Bay. 

 Scale 1 : 170,000. 



Sands and Eeefs 

 exposed at low water. 



liepths. 



etc 25 

 Fathoms. 



25 Fathoms 

 and upwaids. 



3 Miles. 



neighbouring islets no igneous cones have yet been discovered, but the volcanic 

 system again reappears in the Solomon Archipelago. Here, the large island of 

 Bougainville consists from one extremity to the other of a continuous igneous 

 range describing a regular curve whose concave side faces north-eastwards ; Balbi, 

 its culminating peak, has an altitude of 10,170 feet ; but Bagana, situated in the 



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