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developed parallel orientation. The green grains occur as irregular platy masses, some of which show a tendency toward hexagonal outline; they have a refractive index of less than 1-600 but definitely higher than the colourless grains, and almost zero birefringence. The hexagonal-shaped plates show a symmetrical extinction, and the very few grains large enough to enable an interference figure to be obtained have a biaxial character with very small negative (?) optic angle. This material may be a penninite chlorite. Scattered through the entire rock are a multitude of rough rod- like grains up to 0-1 mm., but for the most part less than 0-01 mm., in length, of material with a very high refraction and birefringence. The rods are arranged in a rectangular or rhombic pattern, or in parallel or grid-like aggregates that bear no apparent relation to the outward form or erystallo- graphic orientation of the minerals in which they are now embedded. They may be rutile or leucoxene, The original nature of the rock found in these pods is not known.

A distinctive series of phyllites and schists is exposed on the banks of Swannell River about 6 miles from its mouth. The lowest member exposed in this section is a silver-grey-buff, very fine-grained, sericite-calcite schist, in which dark grey and greenish grey prismatic porphyroblasts of zoisite up to 2 mm. long are embedded without any obvious common orientation in a finely granular schistose matrix estimated to contain about 40 per cent calcite, 40 per cent sericite, and 20 per cent quartz. The zoisite porphryo- blasts are badly corroded by calcite, sericite, and an unidentified clay-like material. The rock contains parallel bands of slightly coarser quartz and calcite, free from zoisite porphyroblasts, about 4 inch thick and occurring at intervals of 6 inches to several feet, which lie at a slight angle to the schistosity and may represent original bedding planes. The zoisite-bearing rock is overlain by about 100 feet of lustrous, dark grey-green, strongly coherent schist. The groundmass of this schist, which is minutely crumpled, is an exceedingly fine-grained aggregate of quartz and sericite(?) con- taining a felted mass of minute, needle-like, pleochroic crystals of fairly high relief and birefringence, which are probably tourmaline. Embedded in the fine groundmass are porphyroblasts of carbonate material with very perfect rhombic outlines. They occur in all sizes up to 1-5 mm. long, but are invariably found in simple, rhombic form, almost completely free from evidence of twinning or cleavage. Most of the rhombs are slightly cloudy, probably because of minute inclusions, but they characteristically contain an outer rim of clear carbonate, which preserves the rhombic outline, though in some grains the clear rim is slightly askew to the clouded ‘core’. Because of their distinctive rhomie outline, and conspicuous lack of twinning, these porphyroblasts are tentatively identified as dolomite. The rhombic form is further emphasized by a rim of quartz in comb-like grains growing per- pendicular to the surface of the carbonate crystal. Accompanying the ‘dolomite’ porphyroblasts are conspicuous tabular porphyroblasts of dark grey-green chloritoid, up to 4 mm. in diameter and 1 mm. thick. The chloritoid shows well-developed polysynthetic twinning, and contains much included quartz, sericite, and carbonaceous matter, which is arranged in a crude, hour-glass pattern in cross-sections and which, with the twinning, gives a radial appearance to many basal sections. The chloritoid porphyro- blasts themselves show some tendency to cluster in radial groups. In general they show no common orientation, and the planes of schistosity of the groundmass are deformed around them, Some beds, rich in chloritoid