264 Transactions. 



McKiNNON Pass. 



Two rocks from this locality, a wehrlite and a gneiss, liave been recorded 

 by Marshall. The present specimens, with one exception (the first enmne- 

 rated), were collected on the western side of the pass. 



Hornblende Schist (C 1). — From the Clinton Valley, near the Pompelona 

 Huts. In the hand-specimen this is a dark-greenish rock, with cleavage- 

 faces of hornblende plainly visible. Under the microscope more than half 

 of the rock is of brownish-green and bluish-green hornblende, with numerous 

 inclusions of rutile and ilmenite. The feldspar is oligoclase, and some quartz 

 is present, as well as a few shreds of biotite and muscovite. 



Gneiss (M 1). — This is a distinctly foliated whitish rock, with quartz 

 and muscovite clearly visible to the eye. In section it is composed of much 

 quartz, plagioclase, and microcline, biotite and muscovite, epidote in grains, 

 and sphene. The elements have a rudely parallel arrangement, strain- 

 effects occur, and the structure is partly cataclastic. 



Diorite Gneiss (M 2, and M 4— 8, 11-15). — These specimens, all from the 

 western side of the top of the pass, include a number of distinctly and in- 

 distinctly foliated rocks, showing hornblende freely, and occasional garnets. 

 In section they are composed of brownish-green and blue-green hornblende ; 

 biotite in broad plates quite subordinate to the hornblende ; occasional 

 muscovite ; and much epidote, both colourless and yellow, in crystals, 

 grains, and granular aggregates. The feldspar is oligoclase, usually clear, 

 with quartz in varying amoimt, but sometimes an important constituent. 

 Rutile is plentiful as brown grains and needles, titanite is also present at 

 times, and an occasional garnet. Cataclastic structure is frequent. 



Hornblende Epidote Schist (M 3). — A dark-grey indistinctly foliated rock, 

 composed of greenish-blue and greenish-brown hornblende, biotite sub- 

 ordinate in amount to the hornblende, muscovite, a little feldspar, much 

 quartz, and a large amount of epidote ; rutile grains are common. This 

 rock is apparently a variety of the diorite gneiss in which feldspar is prac- 

 tically absent. 



Am/phibolite (M 9). — A dark rock composed chiefly of hornblende. In 

 section it is composed of the usual hornblende, greenish-brown and -blue 

 in colour, forming seven-eighths of the rock ; occasional muscovite ; much 

 epidote ; and brown grains and needles of rutile. 



Gabbro (M 10). — A dark-green rock, distinctly schistose, with greasy 

 feel. In section it appears markedly cataclastic, and composed of greenish 

 hornblende much crushed and fibrous, some apparently derived from the 

 pyroxene. There occurs also greenish faintly pleochroic diallage ; en- 

 statite ; with serpentine and talc, which may have been derived from the 

 olivine, but undoubted evidence of this is lacking. Granular sphene is 

 common, and a considerable amount of feldspar, untwinned, and probably 

 of secondary origin, being quite clear, but crowded with needle-like crystals 

 of pale-green colour and with oblique extinction, in all probability actino- 

 lite. A part of this clear mineral may be secondary quartz. Unaltered 

 feldspar occurs in small amount, the grains being completely crushed. The 

 rock appears to be a crushed gabbro or wehrlite. 



Anita Bay ^Milford Sound). 



Captain Hutton (11) has described hornblende diorites and enstatite 

 gabbros from Milford Sound, specially from Harrison's Cove, and Dr. 



