t: si';l:V^ ; A; NATURALIST IN THE PACIFIC CHAP. 



plateau, from which it rises, will be laid bare ; and the small surround- 

 ing islands that are situated upon it, such as Yanganga, Kia, Mali, 

 Rambi, Kioa, &c., will be included in the area of Vanua Levu. 1 



Excluding for the moment the effects of denudation, which have 

 been very great, we shall be able to discern some of the stages of 

 the building-up of the island during the emergence or upheaval by 

 looking at the map and reversing the process in imagination. A 

 subsidence of only 50 feet would cause the Natewa Peninsula to be 

 isolated by a sea-passage along the line of the Salt Lake ; whilst 

 several islands would be formed along the northern and southern 

 coasts, and the Naivaka Peninsula would become detached. If the 

 subsidence extended to 300 feet, the sea would flow over a large 

 portion of the island, where it would regain what was not many 

 ages since its own, an area of basaltic plains, which by their pro- 

 longation under the sea form the great submarine plateau. A 

 subsidence of 1,000 feet would break up the remaining elevated 

 axis of the island into a number of lesser portions ; and after 

 a total lowering of 1,800 feet there would exist only a few scattered 

 islands, the arrangement of which would show but little relation to 

 the present form of Vanua Levu. At either end of the area there 

 would arise from the sea the isolated volcanic peaks of Seatura and 

 Ngala (Mount Freeland) ; and between them would be situated 

 four or five long narrow islands, together with a group of small 

 islands and islets where Na Raro and the other acid andesite 

 mountains of the Ndrandramea district now lie. 



As might be partly expected, there is in the surface-configuration 

 of the interior of Vanua Levu an absence of that simplicity of con- 

 tour which exists in a volcanic island of supra-marine formation, 

 as for instance in the large island of Hawaii where the three great 

 volcanic mountains of Mauna Kea, Mauna Loa and Hualalai 

 together with the older Kohala range, determine the form of the 

 whole island's surface. 2 Here in Vanua Levu there is, on the con- 

 trary, but little order amongst its physical features. The rivers 

 often run obliquely with the sea-border, whilst mountains frequently 

 rise at the coast and plains lie far inland, and the view of the elevated 

 interior, as obtained from one of the peaks, presents in many parts 

 a series of mountain-ridges running athwart the island's axis. 



1 In the case of the island of Faro in the Solomon Group, I have described 

 a similar process of island-building. (Geology of the Solomon Islands, p. 37.) 



2 In 1897 I spent several months in travelling over this island and ascended, 

 sometimes more than once, the three great volcanic mountains. Perhaps at 

 some future time I may renew my examination of this interesting region. 



