454 Transactions. 



Captain Hutton. The quartzites are grey in colour, and consist of rolled 

 quartz grains of fair size, with only very subordinate feldspar, united by a 

 clear cement, which is of the nature of a crystalline outgrowth from the 

 grains. Moreover, the indurated shales of Hector are probably little more 

 than the c^ay-slates of Hutton. The general strike of the beds is south-east 

 and north-west. No fossils have been found. 



i\ssociated with these rocks are rather numerous intrusions of igneous 

 rocks. These have been recorded by several observers. Hutton, in the 

 paper above referred to, says that associated with the Kaikoura sandstones 

 are dykes of diorite. Hector, in his geological map of Otago (in 1864). 

 has diorite rocks shown at such places as Oraka Point, Pahia Hill, and 

 Wakapatu Point. Further, in the New Zealand Mines Record, vol. 3, ap- 

 pears the statement that the Longwood and Takitimu Mountains consist 

 partly of a n:assive development of diorite and syenite in mountain masses 

 and in strong intrusions aniong sedimentary formations. 



An examination of the district confirms these statements to a certain 

 extent. Three distinct types of rock have been identified by me. These 

 occur as giant intrusions, for the term " dyke," usually associated with 

 minor intrusions, very incompletely describes these. The outcrops of 

 diorite at Oraka Point, Pahia Point, and Wakapatu Point, mentioned by 

 Hector, but not mentioned by Hutton, were confirmed ; and, further, 

 another distinct outcrop was noticed on the edge of the beach near Orepuki 

 Township. Further, the whole district extending from Orepuki inwards and 

 from Round Hill along the base of the Longwood as far as Colac Bay was 

 also found to consist of this same rock. Whether the outcrops at the 

 points before mentioned are just branches of this one great intrusion or 

 not, it is hard to say, for the outcrops cannot be followed up on account 

 of the bush ; but it seems extremely likely. 



As this diorite rock forms the whole rock-mass of the Round Hill dis- 

 trict, we shall defer any further consideration of it till we come to describe 

 the minute geology of the Round Hill Claim. 



In addition to the diorite outcrop, two intrusions have been observed 

 by us. It is a remarkable fact also in this connection, that, though both 

 Sir James Hector and Captain Hutton have separately examined the coun- 

 try under re\iew, neither of them has observed either of the two intrusions 

 mentioned below. 



A reference to the map will show that both outcrops occur on the 

 eastern flank of the Longwood Range, and consist of (a) melaphyre 

 and (b) granite. It is to be noted, however, that Hutton in several places 

 speaks of rocks which he calls " argillites." Also, these he says occur in 

 the Kaikoura formation n various places, and he defines the term " argil - 

 lite " as a name given to a rock formed from thick l)eds of clay that have 

 undergone a sufficient amount of metamorphism to obliterate the lamina- 

 tion, while it has not been sufficient to induce any signs of foliation. 



Further, argillite, he says, is much jointed in several directions so as to 

 break into irregular rhombohedra. Now, this melaphyre is a rock bluish - 

 green in colour, and with none of the appearance usually associated with 

 igneous rocks ; no minerals can be identified in hand-specimens, and no 

 cleavage-surfaces are anywhere evident. Also, a rough jointing is some- 

 times seen in it, probably a relic from the days when it was an undecom- 

 posed basalt. It is just possible, therefore, that what Hutton calls an 

 argillite may be here, at any rate, a me^aphyre. Whatever may be the 



