94 Capt. F. W. Hutton on the Origin of the 



Let us now see what palaeontological evidence there is to 

 fix the date of this upheaval. Marine strata belonging to the 

 Pareora system, and containing, so far as we know at present, 

 from 20 to 45 per cent, of living species of Mollusca, are 

 found throughout New Zealand from Southland to Auckland. 

 These may be considered as of Miocene age. The next series, 

 in ascending order, shows a very different assemblage of 

 fossils. It is called the Wanganui system, and is widely 

 spread over the North Island. The marine beds contain a 

 number of shells, of which from 70 to 90 per cent, are still 

 living. This system must therefore be referred to the newer 

 Pliocene. No fossiliferous marine rocks of this system are 

 known as yet in the South Island, but it is represented by 

 thick masses of unfossiliferous gravels. Marine deposits with 

 shells of still living species, and therefore of Pleistocene age, 

 are found at various places in both islands, from Auckland to 

 Oamaru and Dunedin*, and, in addition, there are many un- 

 fossiliferous shore-deposits and other indications that a gradual 

 elevation was going on during the whole of the Pleistocene 

 period all round the coasts south of Auckland. While there- 

 lore we have ample evidence in fossiliferous rocks that the 

 land stood at a lower level than at present during the Mio- 

 cene, Newer Pliocene, and Pleistocene periods, there is a break 

 in our geological record in the Older Pliocene of which we 

 have no trace in marine strata. This can only be accounted 

 for by one of two suppositions : either (1) that all the beds of 

 that age have been covered up or have been removed by 

 denudation ; or (2) that during this period New Zealand stood 

 at a higher level than at present, in which case the marine 

 beds would be deposited at a level which is now below the 

 sea, and con sequently inaccessible to us. As we have both 

 Miocene and Newer Pliocene beds in abundance, there is no 

 reason for thinking that the first supposition is correct; while 

 we have good reasons, in the distribution of our fauna and 

 in our old glacier marks, for believing that New Zealand 

 -was considerably elevated in the Pliocene period. The con- 

 elusion therefore is, that our last great glacier epoch was 

 caused by an elevation of the land that took place during the 

 Older Pliocene; or, more precisely, in the interval between 

 the marine beds ot the Pareora and Wanganui systems. 

 Possibly this elevation may have continued in the South 

 Island (lining the whole of the Pliocene, but it was certainly 

 over before the advent of the Pleistocene. In my address 



* Ste Trans. N.Z. Inst. v. p. 387; ' Geolcgy of Otago..' pp. 70, 78; 

 M'Kay, Ueol. lie^orts, 1878-79, p. 84 ; Von ilaast, • Geology of Can- 

 terbury,' p. 3Ub' ; Percy Smith, Trans. N. Z. Inst. xiii. p. 398. 



