MMJNF.TITK i;\l;NKT ROCKS mn.SnV 285 



other epidote. Both changes can be observed in all stages of completion. The biotite 

 is irregular in shape and frequently contains inclusions of recrystallised quartz. It has 

 no very definite relationship to the schistosity and shows all stages of alteration to 

 chlorite with concomitant production of magnetite. Epidote occurs in granular 

 aggregates in addition to that formed directly from the garnet, and the rock may be 

 called an Kpidote-Magnetite-Schist. 



No. 527. (A). This is somewhat similar to the micaceous magnetite gneiss, 

 No. 576, in the hand specimen and shows a very contorted banding. Pink orthoclase 

 is prominent. 



The main structure is granoblastic but relic, zig-zag and lenticular structures are 

 observed microscopically. Magnetite is abundant and mostly in irregular xenoblasts, 

 while a few flakes of micaceous hematite may be observed. A few garnet relics have 

 survived the alteration to quartx, magnetite, and chlorite. In some cases the outline 

 of the original garnet is preserved (Plate II, fig. 1). Much of the chlorite has been 

 derived from the garnet but part has arisen from the alteration of biotite with the 

 accompanying production of magnetite. Muscovite is sometimes intergrown with 

 chlorite Fine granular quartz grains contain inclusions with an arrangement parallel 

 to the schistosity. Orthoclase is present as large relic crystals which are simply 

 twinned and untwinned. Epidote and apatite are present. The rock is a Chlorite- 

 Maffnetite-Gneiss. 



No. 933. The hand specimen is a well-laminated greenish rock with an 

 abundance of biotite, chlorite, and muscovite. Biotite and chlorite form flaky aggre 

 gates which give the rock a spotted appearance. Quartz occurs in convolute veins 

 which follow the schistosity for some distance and then break across it. The laminae 

 of the rock are curved at one end as the result of bending and shearing rock movements 

 which may have accompanied the infiltration of the quartz. 



The structure is lepodoblastic but relic and cataclastic structures are also 

 present. Magnetite is abundant. Small garnets show the usual development of quartz, 

 magnetite, and chlorite, when examined under the high power, but not nearly to the 

 same extent as in No. 527 (A). Quartz occurs both in large grains in the vein and in 

 small grains with an elongation parallel to the schistosity. It exhibits strain polari- 

 sation and the larger grains show cataclasis. Biotite contains a few pleochroic halos 

 around minute zircons and muscovite is very abundant. Granular epidote is largely 

 intergrown with chlorite. The siliceous veins contain biotite and magnetite and relic 

 felspars which are much kaolinised and penetrated by nr.wly formed quartz. The 

 twin lamellae can sometimes be picked out (Plate II, fig. 2). The rock is a Mica- 

 Magnetite-Schist and has the lowest specific gravity of the group (2-83). 



No. 294. This is an interesting magnetite-schist with contorted banding. In 

 part slight shearing movements have resulted in the fracturing of the bands. Thin 

 quartz veins cut across the bands and are later than the fundamental metamorphism. 



