Marshall. — Geological Notes on South-west Otago. 499 



In the gneisses of Milfoid Sound the feldspar is often pierced 

 by epidote needles formed apparently by secondary action. 

 The Darran Mountains appear to be composed in large part of 

 a mica norite, while near the Mackinnon Pass a wehrlite was 

 found. 



In many of these rocks, but more especially in the p}Toxene 

 gneisses, rutile is a frequent constituent, but sphene is practi- 

 cally absent. As noticed by Hutton, there appears to be a 

 general west to north-west dip ; usually the amount of dip is 

 considerable, often over 45°. 



The rocks described from Anita Bay surround the intrusion 

 of dunite and hartzbergite described in a previous paper,* but 

 their relations to the magnesian rocks are not clearly seen. 



Granites. 



Golden Bay, Paterson's Inlet, Stewart Island (A 12) : A white 

 rock on the fractured surfaces, but golden-yellow on weathered 

 surfaces. Section : Microcline microperthite, forming a coarse 

 graphic intergro\\i;h ^vith quartz. The feldspar is somewhat 

 decomposed. 



Preservation Inlet (A 7) : A coarse-grained pink granite, with 

 little mica. Section : The feldspar is slightly decomposed ; 

 some of it is orthoclase, but the greater part is oUgoclase. The 

 quartz contains minute inclusions. The mica is biotite, and is 

 somewhat weathered. 



Granophyre. 



Ruggedy Point, Stewart Island : A dull-pink rock showing 

 no development of crystals. Section shows an intergrowth of 

 feldspar and quartz of a granophyric nature. The feldspar is 

 somewhat decomposed. 



Mica Norite. 



Cleddau River, Milford Sound (H 25) : Hand - specimen a 

 pale-grey rock showing several crystals with schiller surfaces 

 imbedded in feldspars. Section : Feldspar abundant, sometimes 

 with, curved lamellae, labradorite. Large plates of biotite. Some 

 hypersthene and much diallage, both with schiller structure. 

 Occasionally a little quartz intergrown in feldspar in granophyric 

 fashion. 



Wehrlite. 



Mackinnon Pass (H 26) : A dark heavy rock showing much 

 hornblende in the hand-specimen. Section : Brownish - green 

 hornblende showing strong pleochroism constitutes half the 



* Marshall, Trans. N.Z. Inst., 1904, p. 48L 



