212 AUSTRALASIAN ANTAECTIC EXPEDITION. 



Fig. 4. Garnet hypersthene felspar gneiss, No. 785 (3), Cape Pigeon Rocks, showing 

 an association of biotite and hypersthene. A garnet fringe is present between the biotite 

 and felspar. The biotite has in part developed a perforated appearance, and a portion 

 of the flake is bent. Mag. 35 diam. 



Fig. 5. Garnet hypersthene felspar gneiss, No. 785 (2), Cape Pigeon Rocks, showing 

 the intergrowths of felspars and quartz in polarised light. Mag. 45 diam. 



Fig. 6. The same slide as Fig. 5, showing the relation of myrmikoidal felspar inter- 

 growth with the biotite. The lower right consists of biotite sprays and a thin lath of 

 biotite is seen as a dark line from which the felspar vermiculse radiate. Other inter- 

 growths appear as the stage is rotated. A crystal of microcline is situated in the top 

 left hand corner. X nicols. Mag. 65 diam. 



PLATE V. 



Fig. 1 . Garnet rims surrounding aggregates of biotite and quartz in the hypersthene 

 felspar gneiss, No. 785 (2), Cape Pigeon Rocks. A fragment of hypersthene remains 

 on one side of the aggregate. Mag. 45 diam. 



Fig. 2. A crystal of hypersthene surrounded by biotite and an outer garnet rim 

 in the same slide as Fig. 1. Mag. 45 diam. 



Fig. 3. Sprays of biotite issuing from an ilmenite nucleus in the hypersthene felspar 

 gneiss, No. 979 (2), Stillwell Island. Mag. 35 diam. 



Fig. 4. The same field as Fig. 3 in polarised light showing the manner in which some 

 of the sprays open out into felspar intergrowths. Mag. 35 diam. 



Fig. 5. Hypersthene alkali felspar gneiss, No. 947, Stillwell Island. The slide 

 is cut from the garnetiferous portion of the specimen. Biotite, with a rim of garnet, 

 is seen in the upper portion. Garnet, with inclusions of ilmenite, is a little lower on 

 the right, and pyroxene appears on the lower left. Mag. 35 diam. 



Fig. 6. The garnet rims around ilmenite in the same slide as Fig. 5. One crystal 

 of ilmenite has been partly torn out of the slide in the grinding. Mag. 35 diam. 



PLATE VI. 



Fig. 1. A crystal of ilmenite surrounded by biotite and an outer garnet rim in the 

 hypersthene felspar gneiss from the Cape Pigeon Rocks, No. 785 (2). Mag. 45 diam. 



Fig. 2. The serpentine-hypersthene aggregate in the hypersthene felspar gneiss, 

 No. 785 (3), from the Cape Pigeon Rocks. The crystals of hypersthene are partly altered 

 to serpentine and are outlined by seams of garnet. A pleochroic halo is seen in the 

 lower right. Mag. 35 diarn. 



