438 PROCEEDiNGS OF SECTION E. 



surface was considerably beneath the present sea level, and the 

 absence of fragments of Mesozoic rocks in the Cainozoic conglome^ 

 rates suggests that no such rocks were formed in the Fiji area ; in 

 other words Viti Levu was probably a land area throughout Mesozoic 

 and perhaps Palaeozoic times. 



In the New Hebrides Mawson says a fold ridge was developed in 

 Miocene times, but not before mucli Miocene limestone was deposited. 

 Volcanic eruptions are mentioned by him as associated with the 

 formation of the Miocene folds. 



New Zealand, it is agreed by all those who have worked at this 

 subject, was during the Miocene an area of pi-onounced subsidence, 

 but there is much diversity of opinion as to the extent of the rocks 

 that are to be regarded as of Miocene age.* Sir James Hector classed 

 few of the South Island Cainozoic sediments as Miocene. He even 

 thought them to be in part at any rate of late Mesozoic age. Captain 

 Hutton tlioxight that the greater part of thean were of Oligocene age. 

 Professor Park since he left the Geological Survey under Sir James 

 Hector has classed nearly the whole of these sediments as Miocene, 

 and this view, which was first adojited by the writer in 1902, is the 

 one that he still holds. The gTeat thickness of the sediments thus 

 classed, their general occurrence througiiout both islands, and their 

 fiequent high elevation above sea level, proves that the Miocene 

 depression was prolonged, general, and severe. It certainly affected 

 the New Zealand plateau as far as Campbell Island in the South, and 

 as far as the Chatham Islands in the East. 



During the Miocene and probably towards its close volcanic 

 action became prominent in rnanj^ localities. Apparently in all cases 

 elevation was tlien in progress. This was certainly the case at 

 Dunedin, and though in some other New Zealand localities the- 

 evidence is somewhat less decisive, there is little reason to doubt that 

 an upward movement was in progress at Banks's Peninsula, Oamaru,. 

 Taupo region, and Coromandel Peninsula, and many localities to the 

 north of Auckland. The same appears to have been the case at 

 Campbell Island and at the Chathams. 



The fact that there is a nearly continuous fringe of Miocene- 

 rockn round tlie coast line of New Zealand dipping below the sea 

 level, while inland they visually occur at much higher levels, some- 

 times reaching to an elevation of 4,000 ft. above sea level, may,, 

 perhUj-*-;, fairly be taken to prove that the interior portions of the 

 land Avere more affected by the movements than the margin. This 

 elevation was affected by local folding only. 



Elevation and volcanic action were associated towards the close of 

 the Miocene in the New Hebrides, and in Fiji. In both of these 

 islands the volcanic material was andesite, as was the case in the- 

 Noi-Jh Island of New Zealand. In the South Island the rocks were 

 more basic — usually dolerites or basalts — but in Dvmedin there were 

 important alkaline eiiiptions as well. Basic rocks were emitted at 

 Campbell Island, ChatJiam Islands, and probably at the Auckland 

 Islands at this time. 



This movement of elevation appears to have been continuous up 

 to tlie present time in the Fijis ancl in the New Hebrides, wliere the 

 erupted matter has changed fiom andesite to basalt in tlie later 



