Hill. — Taupo Plateau and Lake. 449 



(83rd) milestone marks the watershed between Taupo and the 

 Rangitikei River : but it is important to observe that the high 

 ridge runs in the direction of Ruapehu and Ngauruhoe, whilst a 

 glance at these mountains from the high plateau between the 

 two slopes shows that the original drainage-area was to the 

 eastward of the present Lake Taupo. Thus it seems that at 

 one period in the history of volcanic activity a line of volcanoes 

 existed twenty miles or more to the eastward of the present line, 

 just as they did to the westward, and that from these volcanoes 

 or great fissures issued sheets of lava of vast extent, with 

 which no modern outflow in this Island can be compared. 



It will have been noticed that from the 83rd to the 96th 

 milestone there is a sudden fall to the lake. The fall is very 

 noticeable when proceeding by coach, as old margin-lines or 

 basins are to be seen, showing by their gradual slope what were 

 at one period in the history of the plateau sloping banks to a 

 large lake, equal in extent to Taupo itself, but now a dry area 

 of pumice mounds, covered here and there with tussock-grass, 

 hardy Dracophyl! um, and a few stray gentians and alpine plants. 



But it is necessary to obtain a full idea of the general character 

 of the country in order to understand the great changes that must 

 have taken place to bring about the present conformation of the 

 district. The valley of the Rangitikei is much more than a 

 mere Post-Tertiary and Pliocene area, as the geological map of 

 the Island has it. The high ridge running between the Taupo 

 Lake and the Rangitikei Valley in a north-westerly direction 

 separates farther in the direction of the Kaingaroa Plain the 

 drainage of the Waikato River from that of the Rangitaiki ; 

 but this was not always so. The lava-beds that cover the plateau 

 preceded the deposition of the pumice and attendant volcanic 

 grits and stones, and we have the fact that the swamp-area in the 

 vicinity of the 68th milestone is much lower than the general 

 area of the surrounding hills, which are composed wholly of 

 rhyolitic lavas. Before the distribution of the pumice in such 

 abundance over the Taupo Plateau it seems as if large volcanoes 

 extended more to the eastward and ran across the plain in a 

 north-westerly direction, crossing the present line of volcanic 

 intensity. For many miles ridges can be traced from the coach- 

 road between the Rangitikei River and Opepe, running in the 

 direction of Wai-o-tapu. Many of these present the appearance 

 of chimneys, and convey the idea that they are the remnant of 

 crateral walls of volcanoes that once played an important part 

 in the history of the volcanic area. 



It is certain that the time was when Lake Taupo did not 

 exist, and there could have been no Waikato such as is known 

 to-day. The drainage or watershed of the country was very 



29— Trans. 



