Hill. — On the Geology of Haivke's Bay. 393 



through three river-basins — viz., the Wainui, the Akiteo, and 

 the Manawatu — the two former emptying their waters into the 

 ocean on the East Coast to the south of Cape Turnagain, whilst 

 the Manawatu discharges its waters into the ocean in the 

 South Taranaki Bight, a few miles to the west of the Foxton 

 Township. There is a great difference in the character of the 

 country drained by tliese rivers. The Manawatu drains an 

 area which is essentially Pliocene and Post-pliocene, whilst 

 the country drained by the Akiteo and Wainui Kivers belongs 

 either to the Older Tertiary or to the Younger Tertiary series. 

 After quitting the Kuahine Mountains the Manawatu passes 

 through a valley made up entirely of young deposits, except in 

 the single instance of the Manawatu Gorge, below Woodville, 

 which separates the Tararua from the Ruahine Mountains. 

 The valley extends from the Ruahine to the Puketoi Ranges, 

 and is important as being, as far as the gorge at least, the re- 

 mains of an enormous rift or subsidence which has been filled 

 from the products of streams derived in great part from the 

 volcanic district which is now separated from the area known 

 as Hawke's Bay district by the Ruahine Range, which was 

 slowly rising as the rift took place, and was no doubt the 

 primary cause of the rift. 



The Ruahine rocks towards the south are made up mainly 

 of sandstones, having a great similarity to the New Red Sand- 

 stone of England. When climbing to the trig, station known 

 as Wharati, at the south end of the range, a short time ago, I 

 noticed that the Maitai slates, which are exposed at Mahara- 

 hara, and which thicken out further northward, were but 

 slightly exposed here. Large boulders of jasperoid quartz 

 overlying conglomerates were met with about 1,200ft. 

 above sea-level ; and at the highest elevation where there are 

 traces of settlement blue fossiliferous clays were exposed, 

 resting against the slates unconformably. I have seen them 

 in a number of cases elsewhere. Beyond this point the sand- 

 stones appeared, and no other kind of rock w^as seen up to the 

 trig, station, where every exposure shows the fine-grained 

 compact sandstone. In the Ruahine, immediately opposite 

 Dannevirke, the sandstone appears in connection with splintery 

 or drossy slates, but the upper rocks are sandstone, with here 

 and there traces of a compact conglomerate of the millstone- 

 grit type. The same kind of grit appears in the Whakarara 

 Mountains, between Hampden and Kereru, and it may be that 

 the latter range was connected at one time with the Ruahine 

 in the direction indicated by the grit stone. The whole of the 

 valley between the Ruahine and the Puketoi Mountains is 

 made up mainly of Post-tertiary deposits. They belong to 

 what may best be described as the Kidnapper pumice and con- 

 glomerate series. These beds, which are very thick in places. 



