are determined by the planes of schistosity which here dip gently to the west, while the cliffs follow joint-planes almost perpendicular thereto. To the east of this Mount Aspiring (9957 feet), the “New Zealand Matterhorn,” probably the remnant of a great monadnock, rises 2000 feet above the general summit-level. Geology and Petrology. The Bryneira Range. Park (1887) described this range as a syncline composed chiefly of Maitai and Te Anau rocks, the former being grey, blue, and red fissile slates and impersistent masses of limestone with interlaminated sandstones, striking meridionally with almost vertical dip, the latter consisting of massive sandstones of all shades of green and aphanitic breccias in contact with the serpentine near the head of the Hidden Falls Creek, but separated from them at the low saddle by an indurated grey pyritous rock. They are everywhere intersected by dykes of grey “syenite and granite.” The western foot of the range he describes as “Kakanui” rocks like those of the Skippers Range—hard, grey, micaceous sandstones, blue calcareous schists, soft micaschist with a peculiar wavy or corrugated structure. It may be doubted, however, whether there is good reason for the distinction of three sedimentary series. Microscopical investigations show that the rocks on the western foot of the range (north-eastern shore of Lake Alabaster, Localities 2 and 3, are very fine-grained pale apple-green, jointed but not markedly schistose (2480, 4731), consisting of quartz and albite in grains rarely more than 0.005 mm. in diameter clouded with dust-like grains of epidote (?) among which are small (0.01 mm.) plates of sericite often, but not always, elongated in the direction of incipient schistosity. Occasionally small unoriented plates of colourless chlorite are present. In other rocks from the same neighbourhood (4842, 4843) the grain-size (0.08 mm.) is larger, the schistosity more pronounced and the feldspar grains a little elongated. A chloritic pseudomorph after augite may occasionally be recognised in rock which seems to have been originally tuffaceous. A much less altered phase of such rocks (4861) was found at Homer's Saddle (Locality 4) six miles further south, a mineralogically reconstituted crystal-tuff (albite, chlorite and epidote) in which are abundant larger feldspar grains 0.2–0.5 mm. in diameter. This rock shows only slight traces of incipient schistosity, but is associated with a strongly sheared, minutely granulated phyllonite (4860) in which thin bands of quartz-albite granules (0.01–0.02 mm.) and some sericite alternate with bands rich in sericite, dusty epidote and occasionally finely divided carbonaceous matter. Between these two localities near Locality 3 on the north-east shore of Lake Alabaster, Burr obtained apparently in situ, but possibly from a massive landslip, a rather finely granular keratophyre (4847), with but little sign of schistosity. It contains phenocrysts of albite (Ab94) up to 3 m.m.* This is merely a pass over a spur projecting into the Lower Hollyford Valley; not the well-known saddle at its head.