WoHTH. — PetroJogical Notes on South Victoria Land Rocks. 493 



Western Mountains, 4. — A dark basaltic rock. Groundmass pale 

 brown. Consists of small brown augites and lath-shaped feldspars, with 

 numerous crystals of magnetite. Some of the augite shows enclosures 

 along both cleavages, giving well-defined dark lines. More or less this 

 feature occurs throughout the slide. Olivine is present in much larger 

 forms, colourless, occasionally with fair crystal outline, with inclusions of 

 magnetite and sometimes of the groundmass. 



Western Mountains, 5. — A thin slab, apparently of grey micaceous 

 slate. Section cut parallel to cleavage. Much pale-brown mica, which, 

 being largely cut parallel to the base, affords a fairly uniform tint 

 throughout the slide, and appears as if filling the rle of a g round in which 

 the othei' minerals are set. Exhibits moderate pleochroism, and in con- 

 vergent light shows a slight separation of the cross into hyperbolae. Short 

 prisms of tourmaline of pale-green colour are rather common, and are very 

 miiformly distributed. There are numerous subangular granules of clear 

 untwinned feldspar. Filling the interstices between the other constituents 

 is a substance white by reflected light, mottled with palest green by trans- 

 mitted light, showing crystal granular and fibroiis structure with high tints 

 between crossed nicols ; the constituents are in much too minute form for 

 identification. Dusty ferrite stains the slide in places, and magnetite is 

 somewhat sparsely distributed throughout. Altered sedimentary. 



Western Mountains, 6. — Soft brown rock, lighter in colour and softer 

 after passing 9 mm. to 10 mm. from exterior. G^laciated. Contains 

 rounded sand-grains. A bright brown tuff with rounded fragments of 

 feldspar, some striated, and less-numerous olivine fragments. A few inclu- 

 sions of white and black rock minutely speckled, and also of brown glassy 

 rocks with feldspar laths. Tuff. 



Western Mountains. — The collection also includes a fragment of kenyte ; 

 a granular felsite, apparently hornblendic ; and some granites or diorites. 



Granite Harbour. 



Granite Harbour, J. — Compact horny texture, dull - brown rock, evi- 

 dently a felsite, with small pink porphyritic feldspars. Small dark spots 

 (1 mm. largest) rather widely scattered. Mica in somewhat granular form. 

 Groundmass minutely crypto-crystalline, pink in shade, strewn with green 

 microlites (pleochroic from browner to bluer shades). The longer axes 

 of these microlites lie in one general direction, and the mineral is almost 

 certainly mica. A very rare grain of magnetite occurs. Porphyritic feld- 

 spars, some entirely clouded with red decomposition-products, others in 

 parts quite clear and colourless with irregular streaks of cloudiness and a 

 hatching of lines of same. The feldspars are clearly defined against the 

 ground, and appear to be in large part microchne. Here and there the 

 green mineral invades them in somewhat massive form, and it also fills 

 cracks in the rock. 



Granite Harbour, 2. — Fine-grained granitic texture, white feldspar, black 

 mica, quartz slightly stained in places. Feldspars slightly clouded locally, 

 practically all oligoclase. The quartz contains small fluid inclusions, with 

 bubbles, and some empty cavities. Much brown mica ; pleochroism pale 

 straw to dark greenish-brown, almost black ; gives practically uniaxial 

 figure in convergent polarized light. Apatite prisms are frequent, in aciculai- 

 form, the central parts much darkened by some dusty black substance, 

 which lies mainly in a series of planes parallel to the base. Pale granular 

 sphene, at times with a core of titanic iron-ore. Quartz-diorite. 



