738 
latli-sliaped crystals of felspar, and also magnetite in botli large and small grains. e 
pyroxene element has been changed into viridite. There are a few larger crystals o o 
ortJioelase and 'plagiorlase felspar. . . 
30. Hornblende schist, from Sandy Creek. A Tery beautiful slide containing green 
hornblende, having a linear arrangement, and showing very perfect cleavage parallel to tie 
plane of symmetry and faces of the prism. Those crystals contain enclosures of apatite an 
epidote. iloautifully twinned crystals of plagioelase felspar, some of which appear to have had 
a secondary growth ; they contain enclosures of apatite. A few solitary crystals of orthoc ase 
felspar. There are a few specks of yaarfs ,• magnetite \s, xvce. 
31. Qarnetiferons granite, from the Pontland llangc, at the head of Sandy Creek. ^ T e 
slide is much broken. The minerals that can be distinguished are Qfuartz,, containing 
prismatic enclosures of apatite ; plagioelase felspar ; mica, and garnets. 
33. Hypersthene rock. A dark-coloured, highly crystallised rock, from a dyke on 
Daunton’s Hill, Upper Cape. Htjpersthene is the principal mineral. It is a green mineral, 
possessing strong pleoehroism ; the cleavage is prismatic. The mineral extinguishes parallel 
to the planes of cleavage. It contains several hexagonal enclosures of apatite, and also of 
quartz; streaks of ywar/z follow the cleavage planes. It also contains enclosures od magnetite. 
Quarts in large plates is the next mineral in importance ; it is full of very minute enclosures. 
Brown mica occurs in the hypersthene, and also in a semi-transparent iron compound 
leucoxene, of which mineral there is a large amount in the slice. 
34. Hornblende schist, from Daunton’s Hill, Upper Cape. A crystalline rock resembling 
a coarse diorite, except that the hornblende occurs move or less in layers. This is the rock in 
contact with which the loaders on Daunton’s Hill ceased to carry gold. The rock is made up 
to a large extent of very beautifully twinned crystals of oligoclase felspar, full of small 
hexagonal enclosures of apaiiie, and also enclosures of leucoxene. Hornblende, well-cleaved, 
and containing also enclosures of apatite. Quarts in small blebs. Magnetite changing around 
its edges into leucoxene. 
35. ft highly crystalline schist, from Mount Elran, Upper Cape. Quartz \s the principal 
mineral ; it contains enclosures of small garnets. Entwined around the quartz is green 
hornblende. Plagioelase felspar. Very small garnets occur throughout the rook. 
36. A fine-grained, grey micaceous granite, from Mount Elvan, Upper Cape. The 
minerals in the slide arc — Plagioelase felspar, some of which is much decomposed. Well- 
cleaved soliite mica ; and quarts with acicular crystals of apatite, and other minute enclosures. 
38. A purplish porphyry, from the Cape Hirer, near the Pot-hole Lead, Upper Cape. 
It consists of an amorphous ground-mass, showing fluxion-structure, and full of ferrite and 
magnetite. It contains piorphyritic crystals oi plagioelase felspar. 
40. Olivine basalt, from Mount Black. A compact black rook, possessing polarity. I he 
slide shows a microcrystalline ground-mass, containing numerous specks of magnetite, with 
crystals of olivine, a few crystals of felspar, and specks of augite. 
42. Olivine basalt, from the Tableland, Oxley Creek, a somewhat scoriaceous basalt 
containiug zeolites. The rock consists of an interlaced mass of acicular crystals of felspar, 
with crystals of olivine throughout it. Some of the olivine crystals are much decomposed 
around their margins, and along cracks in the crystals. Magnetite is comparatively rare. 
43. Basalt, from the Basaltic Wall, Lolworth. A highly scoriaceous basalt. The rock 
was a difficult one to cut, and the slice is very small. It shows an interlaced mass of crystals 
oi plagioelase felspar, with small specks of olivine. 
Note. — The microscopial slides described above were prepared for me by Mr. A. W. 
Clarke. 
