THE METAMORPH1C ROCKS OF ADELIE LAND. 8TILLWELL. 211 



Fig. 5. Epidosite, No. 415, Cape Denison, showing epidote and felspar. The 

 dark mineral in the upper half is sphene, and a crystal of hornblende is situated in the 

 left centre. It occurs as a clot in the amphibolito, No. 628. Mag. 35 diam. 



Fig. 6. Biotite hornblende schist, No. 4, Cape Denisop, showing long prisms of 

 hornblende intergrown with biotite. This rock occurs as a clot in the amphibolite 

 bands. Mag. 35 diam. 



PLATE III. 



Fig. 1. Diablastic structure, or a secondary intergrovvth of quartz and felspar 

 in the hypersthene alkali felspar gneiss at Madigan Nunatak. X nicols. Mag. 35 diam. 



Fig. 2. A similar, but much finer, diablastic intergrowth in the same slide as Fig. 1. 

 Mortar structure is seen and the intergrowth has developed in the crush area. X nicols. 

 Mag. 35 diam. 



Fig. 3. Hypersthene alkali felspar gneiss, No. 949, Stillwell Island. It is a rock 

 similar to " charnockite " and occurs in dyke form. Mag. 35 diam. 



Fig. 4. Garnet cordierite gneiss, Cape Gray, showing the finely granulitic character 

 of the cordierite. The large clear crystal at the top is quartz. X nicols. Mag. 35 diam. 



Fig. 5. This and the following illustrate a slide cut across the junction of the cyanite 

 biotite gneiss with the amphibolite at Garnet Point, No. 781. This figure illustrates 

 the hornblende part of the slide. The dark mineral is hornblende, and the colourless 

 mineral with which it is intergrown is cyanite. Mag. 35 diam. 



Fig. 6. The biotite part of the slide, No. 781. The dark mineral is biotite, and the 

 mineral with high refractive index is garnet. The colourless portion consists of cyanite 

 and quartz chiefly. Mag. 35 diam. 



PLATE IV. 



Fig. 1. Plagioclase pyroxene gneiss, No. 794, Madigan Nunatak. Plagioclase, 

 pyroxene, and ilmenite with a very little hornblende are visible. The narrow granulated 

 selvages around the pyroxene crystals can be detected in part. The rock has practically 

 the same percentage mineral composition as No. 773 (Plate VI., fig. 5). Mag. 35 diam. 



Fig. 2. Hornblende plagioclase pyroxene gneiss, No. 759, Aurora Peak. The 

 darker hornblende is readily distinguished from the pyroxene on the one hand and from 

 the ilmenite on the other. The rock has practically the same mineral composition as 

 No. 794, Fig. 1, except that part of the pyroxene is replaced by hornblende. Mag. 35 

 diam. 



Fig. 3. Garnet hypersthene felspar gneiss, No. 785 (2), Cape Pigeon Rocks. A 

 crystal of ilmenite is surrounded by a zone of biotite and quartz. A little ilmenite and 

 garnet are scattered through the zone which extends as a bight into a large hypersthene 

 crystal on the left and top of the figure. Mag. 45 diam. 



