HuTTON. — The Geological History of New Zealand. 171 



tephrites,''' a rock not known from any other part of New 

 Zealand . 



Before going any further I should like to point out that 

 each of our geological systems, from the Hokanui to the 

 Oamaru, seems to have been ushered in by volcanic outbursts, 

 which were followed by depression and subsequent elevation. 



Miocene Period. 



Pareora Series. i — Marine rocks of Miocene age, with from 

 20 to 65 per cent, of the fossil molluscs belonging to still 

 living species, and with the teeth of the shark Garcharodon 

 megalodoii, are found in many parts of the New Zealand 

 coasts ; while in the interior they go up to a height of 3,000 ft. 

 above the sea in the South Island, and to not less than 4,000 ft. 

 in Hawke's Bay. In a few places— such as Pomahaka, Wai- 

 hao, and Mokau Eiver — they are underlain by beds of coal. 



About 235 species of MoUusca have been described from 

 the Pareora series, and eighty-four from the Oamaru series, 

 and fifty-one of these species are common to both ; so that 

 both series are closely connected palseontologically. Never- 

 theless, the Pareora series very often lies unconformably on 

 the Oamaru series, the latter having undergone considerable 

 denudation before the former was deposited. Examples of 

 this may be seen at Palmerston South, Oamaru, Elephant 

 Hill, Kakahu, Greymouth, and Koniiti Point, in the Kaipara ; 

 while at other places — e.g., Southland, Waiau (in Amur! 

 County), Hawke's Bay, and Kawau — the Pareora series rests 

 upon Mesozoic or Palaeozoic rocks. From this we infer that 

 at the end of the Oligocene period the land was slightly 

 elevated for a short time and then subsided to a lower level 

 than before. New Zealand in the Miocene period being re- 

 duced to a group of islands. 



The marine rocks are chiefly soft sandstones and clays,^ 

 but limestones are largely developed on the east coast of the 

 North Island from Wellington to Hawke's Bay. 



The fossils are remarkable for the large size of the shells 

 belonging to the genera Oatrea, Pecten, Lima, Gucullcea, 

 GrassateUa, Gardiimi, Gytherea, Dentaliiim, Pleurotomaria, 

 Turbo, Scalaria, Turritella, and Natica, which give the fauna 

 quite a tropical appearance. And this evidence is much 

 strengthened by the fact that the fruit of palm-trees has 

 been found not only at Mongonui in the north, but also when 

 making the Livingstone Tunnel near Oamaru. Several of our 



* Ulrich, Report Aust. Assoc. Adv. Science ; Christchurch, 1891, 

 p. 127. 



t I include here the Waitemata series of Sir James Hector's Cretaceo- 

 tertiary and the Mount Brown series of his Upper Eocene, as well as his 

 Upper and Lower Miocene formations. 



