HiLi.. — Napier to RuiuoKja and the Taupo Plateau. 291 



at one time a scries of lakes covered this area. The Raiigitaiki River has 

 its source in some old crateral lakes on the Loch Inver Station. Here 

 trachytes are found in close proximity to the sandstones which top the low- 

 lying hills that form the northern end of the Kaimanawa Mountains. The 

 lakes seem to have been centres of explosive action, and at the place of out- 

 flow, where the water flows into the open country and takes the name of 

 the Rangitaiki Stream, the rhyolites form a lip which has been cut through 

 by the owners of the station by means of blasting, so as to assist in the 

 drainage of the swamp and lake. 



The country has few exposures of rock, but in a creek near the station 

 already named both sandstones and the Maitai slates occur, just as a little 

 lower down the volcanic rocks appear, although no intrusive rocks were 

 met with. 



Following down the Rangitaiki, which runs between high banks, there 

 appear exposures of peat-lignites of some 9 ft. in thickness. These cover a 

 large area between the upper stream and the Rangitaiki Hotel, a distance 

 of some six miles. Whether the beds reappear below the hotel I do not 

 know, but the exposures show that at one time a very large part of what is 

 now pumice-covered country consisted of swamplike areas similar to what 

 are met with and are now being drained in the vicinity of Runanga. The 

 lignite material is made up of Sphagnum, stems of shrubs such as Veronica 

 and Fagus, and a large variety of fibrous roots matted together into a com- 

 pact mass. Overlying the lignite is pumice, very fine in structure, and 

 without pebbles. It is not more than a few inches in thickness, and it 

 appears to have been deposited by water. It is difficult to account for this 

 covering of lignite or vegetable beds by a pumice -deposit, because the fact 

 of a lignite-bed implies a long period of midisturbed growth and decay. It 

 may be that the lignite-beds represent the old surface of the plain before 

 the last great outpouring and spread of pumice, when the country as far 

 as the 81st milestone contained a series of swamplike lakes that spread 

 here and there among the hills forming the head-waters of the Rangitaiki, 

 and even flowed at times over a saddle into the swamp-lakes that begin in 

 the vicinity of Runanga. A low saddle from the Napier-Taupo coach-road 

 to Loch Inver forms the dray-road to the station ; and when viewing the 

 topography of the comitry from one of the higher hills of the district it can 

 be seen that the various lake-areas were at one time joined by low saddles 

 that are not more than 300 or 400 yards in width. In some parts of the 

 lignite-beds there is a thin band of pumiceous clay between the two main 

 lignite-beds ; but everywhere the pumice-beds overtop the lignites, just as 

 the pumice to-day covers the whole surface of the Taupo Plateau. 



Down the Rangitaiki River, ten miles or so from the coach-road, a series 

 of romided hills occur, and these run north-west as far as the track, which 

 divides, one to Galatea and one to the Waiotapu Valley, across the 

 Kaingaroa Plain. At this place there are the remnants of rocks that 

 must at one time have formed an immense crater, the broken-down walls 

 reminding one of old embattlements. It seems as if the country to the 

 north-east of the 81st milestone must have sloped in the direction of Wai- 

 punga, and that the surplus waters, charged with pumice, were carried into 

 the Mohaka River, and thence into the area of Hawke's Bay. 



In a former paper (Trans. N.Z. Inst., vol. 37, p. 415) reference is made to the 

 original dramage from Ruapehu and Tongariro at the time when the present 

 Lake Taupo was the crater of an immense volcano. The suggestion is mad& 

 10* 



