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country a large number of tributary streams, most of them being heavv 

 shingle and pumice carriers. By means of the network of tributaries from 

 the west, the country was bared of a large part of the limestone that covered 

 it at the close of the Pliocene period, being replaced by heavy deposits of 

 shingle and pumice of great thickness, and of a kind that is now character- 

 istic of the country between the Kaimanawa Mountains and Tauranga- 

 Taupo. 



Towards the close of the Pliocene and the opening of the Pleistocene 

 periods great and important changes took place. Great volcanic activity 

 was experienced in the interior of this Island, and the east coast was shaken 

 to its foundations. It was during this period of activity that a large portion 



Fig. 4. — East Coast, showing River Systems as at Present. 



of the coast disappeared and sank beneath the ocean. Hawke Bay, Here- 

 taunga Gulf, Wairoa Gulf, Poverty Bay, and Turanganui Gulf were formed 

 at this time. 



The Great Wairarapa disappeared as a river, and the entire aspect of 

 the water drainage was modiiied. A reference to map fig. 2 shows the 

 condition of the coast and the physical features of the land following the 

 subsidence and the disappearance of the Great Wairarapa river-basin. 



What had formerly been tributaries of a great river now began to form 

 separate basins of their own, and we have the interesting fact that by ordi- 

 nary earth-movements new rivers and river systems may be brought into 

 existence and the facies of a country completely changed. 



