THE VICTORIAN NATURALIST. 19 



obtained in some layers of the basalt at several parts of this 

 coast in long, slender, acicular crystals up to a quarter of an inch 

 in length and of a black colour. 



2. Oligoclase. — Occurring similarly to the Hornblende in 

 irregular fragments in the dykestones near Flinders. It is 

 frequently in larger pieces than the Hornblende, the largest 

 measured being 3}^ inches by 2 inches. It is occasion- 

 ally clear and transparent, but more usually translucent dirty 

 yellow, and much stained with oxide of iron ; much of it is 

 complicately twinned, and shows highly-perfect basal cleavage, 

 also fair cleavage apparently parallel to the macropinacoid. 



3. Biotite is another included mineral in the dykestones, rang- 

 ing up to about I inch in diameter. It is of a black to 

 brownish-black colour, with perfectly developed basal cleavage. 



4. Apatite was also obtained in the dykestone as a good 

 crystal of a dirty greenish colour, and over i inch in length, 

 but comparatively slender, about one-sixteenth of an inch in 

 diameter. The form was a hexagonal prism, and was terminated 

 by a short hexagonal pyramid. The prism broke into several 

 short lengths on extraction, apparently due to imperfect basal 

 cleavage. 



5. Olivine is very abundant in the basalt forming the shingle 

 near West Head and along the coast to Cape Schanck. It 

 occurs as very dark green glassy blebs, thickly strewn through 

 the rock. As there are many stages in the decomposition of the 

 basalt to be seen in this neighbourhood, many changes in the 

 Olivine may also be noted until we meet with a soapy clay con- 

 taining a mineral resplendent with a golden iridescence, probably 

 a hydrated oxide of iron. 



6. Nairolite. — This mineral is most abundant on the coast 

 about 3 miles from Flinders, towards Cape Schanck, in a basalt 

 which is rich in vughs. The mineral closely lines these vughs in 

 acicular rosettes of crystals with a glassy lustre, but silky on 

 fracture, and though in small bundles the crystals are well 

 developed in numerous beautiful colours, amongst which are — 

 pure white, fawn, yellow, pale and dark brown, pale pink, red, and 

 red-brown. 



7. Analcite. — Some fine examples of this mineral occur closely 

 associated with the Natrolite, in clear transparent to milky 

 translucent crystals of the cubic system, usually deltohedra, 

 individual crystals ranging in size from very small microscopic 

 forms up to about three-eighths of an inch in diameter. Contact 

 and penetration twinning is frequently present. 



8. Gmelinite. — Some extremely fine occurrences and crystalliza- 

 tions of this mineral were also obtained in association with the 

 two foregoing. In colour it ranges through pale yellow, yellowish- 

 red, orange, pink, and light to very dark shades of red. Crystals 

 belonging to the hexagonal system, and occurring in simple 



