Henderson. — Surface Fon/is mid Drai ii(i(i('-^ii><fems of Wcsf X(/son. 311 



remains of the Otago peneplain, wiiich is merely the southern continuation 

 of the alpine peneplain of Canterbury and Westland. 



On the west the alpine peneplain is bounded throughout its entire 

 extent by the great alpine overthrust. It occupies a great part of Marl- 

 borough, east Nelson, and Canterbury. Like the other peneplains, it has 

 been subjected to differential uplift, and, on the whole, the uplift has been 

 greater. From the head of the Taramakau to the head of the Maruia 

 the average height of the peaks is about 6,000 ft. ; from Cannibal Gorge 

 to Lake Eotoiti the mean is well over 7,000 ft. ; while north of Lake Rotoiti 

 few of the summits overtop 5,000 ft., and going north the height sinks 

 gradually to 2,000 ft. on D'Urville Island. 



The Areas of DEPRESsioisr. 



The first of these to be considered, the Taitapu depression, is at present 

 occupied to a great extent by Golden Bay. It is bounded on the west bv 

 the Aorere fault, and on the south by a probable fault parallel and subsi- 

 diary to the Cook Strait fault, which passes north of Cape Farewell. Two 

 arms of this depression extend southward along the rift-valleys of the 

 Aorere and Takaka. These two prolongations are filled with three series 

 of deposits. The oldest of these deposits consists of conglomerates, sand- 

 stones, and limestones of probable Miocene age ; the next deposit consists 

 of gravels, and mudstones laid down when the land stood at a lower level 

 — probable age Pleistocene ; the other series of deposits are the gravels of 

 Recent age. 



The Whakatu rift-valley is bounded by the Motueka, Sherry, and alpine- 

 overthrust faults. Its northern depressed end is occupied by Tasman 

 and Blind Bays. The southern end is occupied by a vast deposit of gravels- 

 — ^the Moutere gravels — of Pleistocene age. On the south these gravels 

 cover — in fact, completely cross at one point — the Murchison peneplain. 

 At numerous points around the edges of the valley the Miocene coal- 

 measures outcrop, and it seems reasonable to suppose they form the floor 

 of the whole valley. 



The Kawatiri rift-valley, separated from the Whakatu Valley by the 

 Murchison peneplain, is bounded by the Tutaki, Matiri, and alpine-over- 

 thrust faults. It lies at a higher level than the areas of depression hitherto 

 described, and is occupied chiefly by the Miocene rocks, the Pleistocene 

 gravels which may at one time have covered the coal-measures having 

 been almost entirely removed. 



The Oweka depression (named from the Maori name for the plains of 

 the Inangahua*) lies between the Victoria and Paparoa peneplains, and 

 extends northward into the valley of the Orikaka, and perhaps into the 

 basin of the Mokihinui. It is bounded by the Mawhera, Inangahua, and 

 Ross faults. Like the other rift -valleys, its floor is covered with Miocene 

 strata, which in turn are overlaid by Pleistocene (Old Man) gravels and 

 Recent river-wash. 



A long depressed strip faces the Tasman Sea, in places sinking in steps 

 from the Paparoa, Lyell, and Mount Arthur peneplains, which bound it on 

 the east. In this coastal strip occur the basement rocks, granite, greywacke, 

 the Miocene coal series, Pleistocene and Recent gravels. 



* Haast : Geol. Explor. of W. Nelson, p. 76. 



