492 Transactions. 



ih. — Less highly vesicular, almost opaque, red in parts, in parts almost 

 black by reflected light. Some feldspar rods scattered sparsely. Olivine 

 freely developed, and some augite. Summit of island, in situ. 



Armitage's Sledge Party, near New Harbour. 



Medium grain, granitic texture, black mica, white feldspar. At one point 

 within a little space four crystals of clear brown sphene, the largest 2-5 mm. 

 by 1-25 mm. Biotite-mica, pleochroism pale olive-brown to very dark 

 greens and browns. A little chlorite, developed at the expense of the mica. 

 Quartz in coarse mosaic, fluid inclusions with small bubbles, some appa- 

 rently empty cavities. Two classes of feldspar. The greater part ortho- 

 clase, but a fair proportion of plagioclase, j^robably oHgoclase. Both are 

 very fresh in patches, much altered here and there. The plagioclase twin- 

 ning shows the occasional shear of a crystal, and also considerable bending. 

 Some apatite. Biotite-granite. Collected on the western sledge journey of 

 1902 by Lieutenant Armitage. 



Western Mountains. 



This collection numbers upwards of a dozen specimens, the wasters of a 

 larger collection of loose rocks picked up by Dr. Wilson when on a sledge 

 journey with Lieutenant Armitage to the southern extremity of the foot- 

 hills of the Western Mountains forming the northern shore of the outlet 

 of the Koettlitz Glacier. This journey was undertaken in December, 1903. 



Western Mountains, 1. — Mica-schist, much dark mica partially leached 

 and iron-stained. A gneissic rock of clastic appearance. Both feldspars 

 and quartz are in interlocked granules, and both appear distinctly 

 fresh. The feldspar is often .striated (symmetrical extinctions 20°), and 

 frequently penetrated by, or includes, needles of apatite. The quartz 

 seems free from fluid inclusions. A few crystals of rutile occur. There 

 is much mica, the more part intensely pleochroic from very pale pinkish- 

 brown to rich red-brown ; associated with this is white non-pleochroic 

 mica, which in certain areas occurs in tracts of long bent blades, stream- 

 ing in a uniform direction, and associated with patches of quartz and 

 feldspar mosaic of fine grain, within which again are small patches of 

 brown mica, otherwise excluded from these portions of the slide. It is 

 to the white mica so developed that the marked schistosity of the rock 

 is due. The whole slide gives evidence that the rock has sustained an 

 intense crush — so intense, indeed, that the quartz-feldspar mosaic is at 

 places reduced to a mere aggregate of powdered material. 



Western Mountains, 2. — A grey rock of rough texture. A few feld- 

 spars are visible, but a rather dull brown-grey mica is by far the most 

 prominent constituent. Mui-h biotite. Face - colours vary from pale 

 cinnamon-brown, with an occasional olive shade, to rich tints of brown 

 in basal sections. Comparatively small patches and blades of hornblende 

 are fairly frequent. The pleochroism is from pale olive to deep blue-green. 

 Very numerous grains and some larger much -altered crystals of augite. 

 showing slight pleochroism from liluish-grey to pink-grey. Large patches 

 of calcite. All in a general confused groundmass of high double refraction, 

 with serpentinous products. There is also, apparently, some secondary 

 feldspar in mosaic form, and some sphene after titanifernus iron-ore. 

 Dioritic lamprophyre. 



