Cussen. — Notes on the King Country. 323 



very doubtful. I believe the latter marl beds are of three 

 different ages, and the tufa beds are contemporaneous with those 

 of the middle period, for reasons which will be shown hereafter. 



Miocene. 



The clay marls, or " blue papa rock," of the Upper Whanga- 

 nui belong, I believe, to this formation. These beds occupy a 

 large area, extending inland from Whanganui to the Tuhua. 

 It is a fine-grained calcareous and argillaceous formation of great 

 thickness ; it can be traced to an altitude of 2,100 feet above the 

 sea on the Hunua Eange, 12 miles touth of Taumarunui, where 

 it is exposed in great masses in the numerous landslips on the 

 mountain sides. The beds dip to the south and the south-west 

 at angles varying from 3° to 15°. They sometimes enclose bands 

 of more compact, harder, and more sandy rocks ; and in the 

 valley of the Otaunui Stream I noticed at one place large 

 partly rounded boulders of tufaceous sandstone (or possibly 

 septaria,) appear, interbedded with the marls. Eesting on these 

 marls, and probably conformable to them, are the tuff beds 

 before mentioned as so extensively occupying the higher area of 

 the plateau. They occur here in a precisely similar manner, but 

 not quite so persistently ; and here they are associated with lava 

 floes of rhyolites and andesites. 



I have said that I considered the marl beds of this part of 

 the district were of three different periods of deposit. I regret 

 that I never met with an opportunity of examining the beds at 

 their junctions. The valleys are here so much covered in with 

 superficial pumice deposits that to obtain sections will be a work 

 of time and trouble. It seemed to me, however, that the tufa 

 beds resting on the lower blue marls lie conformably on that 

 deposit. Besting on the tuffs, again, is another deposit of the 

 same blue-clay marl apparently ; this forms the rock masses of 

 the range west of the Ongarue Eiver, known as Tangitu, Maunga- 

 rahiu, Tapuewahine, etc., through one of the saddles of which 

 (the Paro-o-te-rau) the tunnel on the Main Trunk Eailway is now 

 being formed, and the character of rock being driven through is, 

 I believe, all the " blue papa." Fossils are very scarce in the 

 deposit, and difficult to save ; they crumble away on being exposed 

 to the atmosphere. The beds are distinctly stratified, but I have 

 not ascertained their dip. They are greatly subject to atmo- 

 spheric influences, and, whenever exposed, are quickly channelled 

 by watercourses and removed by denudation. 



At the crossing of the Whanganui Eiver, on the native track 

 between Taumarunui and South Taupo, at a place called 

 Taringapupu, the river bed is scooped out in blue marl rock — 

 whether of the older Whanganui series or the later deposit I 

 cannot say ; and the relative ages of these beds must remain an 

 open question until their fossils are collected and compared. 



