Phillips. — On the Volcanoes of the Pacific. 191 



The one real and prominent fact in regard to the island 

 groups in the Pacific is that they have been upheaved, since 

 which a certain amount of subsidence has followed, but so 

 slight that, as I have said, the Langiis at Tonga still remain 

 much as they were built some three or four thousand years 

 ago. There may be now a period of rest, but even that sup- 

 position I cannot agree with, so many slight changes do I 

 know of taking place. I must say that Milne concludes his 

 book in quite as uncertain a frame of mind as I am myself. 

 The field is so vast and our knowledge so slight. The coral 

 borings at Funafuti may tell us something, but even the sink- 

 ing of a volcanic hill or blister near the equator some 1,500 ft. 

 below the sea after upheaval, somewhat like Palcon Island, 

 but to a greater depth, may only be a local phenomenon, 

 telling us nothing of the general law of lines of activity or 

 subsidence to which I am referring in this paper. 



The opinion of leading geologists belonging to this In- 

 stitute is that there are no "lines of activity," each volcanic 

 rent being local to itself. What, then, of the great line 

 runnmg north to south, bordering the Pacific, in the two 

 American continents? And another line might be drawn 

 fringing the Pacific on the other side — -namely, through Japan 

 and the Kurile Islands. 



Begmning with the phenomena upon the islands where 

 the first two lines of activity intersect each other — viz., the 

 Loyalty Islands : Attention has already been called to the 

 Eev. Mr. Turner's remarks "that Lifu is an uplifted coral 

 formation, the highest land on the islands being about 300 ft. 

 above sea-level ; and Mare a mass of uplifted coral, also bear- 

 ing marks of two distinct upheavals." 



The peculiar formation of the islands lying off the mouth 

 of Nei-afo Harbour in Vavau (Tonga) now require reference. 

 The whole of them appear to be at an exact uniform level of 

 100 ft. to 200 ft. above the sea, evidently showing the same 

 upheaval. They look just as if they were bits of reef up- 

 heaved. In no other way could they have acquired their flat 

 tops and straight sides. " The power which exhausts itself 

 in the eruption of a volcano often shoW'S itself by the changes 

 it produces in the level of the surrounding country." 1 do 

 not think that any land in the three great islands of Tonga is 

 much more than 300 ft. above sea-level ; Tongatabu much 

 low^er. The highest land I know is in Vavau : that island 

 contams a great open grassy plain about 200 ft. high, uu- 

 stocked, owing to the absence of water. The soil of Vavau 

 and the surrounding islands is an excellent rich brown one, 

 evidently volcanic. No doubt this soil came from the original 

 volcanic rock, which has weathered, decomposed, and speedily 

 ■clothed itself with vegetation. 



