F.MiQUHAnsox. — 'Hie rhitinvm Grareh of Ore])ul-l. 453 



General Geology. 



Having got n general outline of the geographical characteristics of the 

 country, we are now in a position to devote some little attention to its 

 general geology. As will be seen from the accompanying geological map, 

 the geological masses we have found represented are six in number— viz., 

 (1) Kaikoura formation, (2) Oamaru formation, (3) Pleistocene, (4) basalt. 

 (5) granite, (6) melaphyre. 



As is usually done, we shall begin with the oldest, the Kaikoura 

 fornuition. 



Captain Mutton, when Provincial Geologist of Otago, in 1872, gave in 

 his paper on the geology of Otago a description, on general lines, of the 

 structure of the west of Otago, which we think it will be highly advisable 

 to make use of here. " The whole of the District of Southland," he says, 

 " is included in an inclined trough of Palaeozoic and Secondary rocks, the 

 major axis of which lies in a south-east and north-west direction, rising to 

 the north-west where the rocks are thrown up and close the upper end of 

 the trough. The lower end, towards the Mataura River, is open. The belt 

 of Palaeozoic rocks that forms the rim of this trough runs from the Umbrella 

 Mountains on the north-east, round by the Takitimu Mountains and Long- 

 wood Range on the west, and passes into the Bluff Hill on the south-west. 

 In its folds are enclosed large masses of Secondary rocks The south-west 

 edge of this trough has been broken down in several places, and Tertiary 

 rocks have been deposited indifferently on both the inside and the outside 

 and overlapping its edge. These have in their turn been largely removed 

 by denudation, and replaced by immense deposits of gravel and silt." 



From this it will be seen that a section across the major axis of the 

 trough taken in the district with which we are at present concerned may, 

 as it actually does, appear as follows : — 



LongMOod Range 



Ray ward's Cap 



55 W ^.^-^^//^///////^YZ/ . W/////^/. ^ •//// A-ZT^TT^-^r^^. ^,^^ 



Fig. 4. 



At / and f/ we have the trough, inside at / and outside at <i. h. Slatop. 

 rj and /. Tertiary rocks. 



The Kaikoura formation of Hutton is a part of the Upper Palaeozoic 

 period, and is also a part of the Te Anau series of Hector, classed in the 

 Upper Palaeozoic also. It is represented in the district by the Longwood 

 Range and its outskirts (see map). Roughly speaking, then, it comprises 

 all that part of Southland extending from near the eastern bank of the 

 Waiau to near the Pourakino River, and from the head of the range to 

 the sea-coast. 



The rocks consist principally of clay-slates and grey sandstones or 

 quartzites. According to Sir James Hector, who reported on the district 

 in 1864, and whose paper appeared in the " Quarterly Journal of the Geo- 

 logical Society " in 1864, these rocks consist of indurated shales with cal- 

 careous sandstones ; but an examination of them leads us rather to support 



