156 R. A. WEARNE AND W. G. WOOLNOUGH. 



are quite fresh and twinned after the Carlsbad and Albite 

 laws. The felspars of the second generation differ only in 

 size, ranging about 0*5 mm. by 0*1 mm. 



Olivine is remarkable as occurring in two distinct gener- 

 ations, a phenomenon quite unusual for this mineral. The 

 earlier formed crystals are magnificent idiomorphic forms, 

 3 mm. by 2 mm., with notably good cleavages. Along the 

 cracks there is a good deal of alteration into serpentine, 

 the fibres standing at right angles to the cracks. Another 

 remarkable feature about these large olivines is that peri- 

 pherally they are moulded on the felspars of the second 

 generation. The olivines of the base are* of small dimen- 

 sions and almost completely serpentinized. 



Augite is in brownish-grey grains and imperfect prisms 

 0*2 mm. long. It is entirely interstitial in character but 

 is not ophitic (granulitic according to Judd). 



Ilmenite occurs in plates and irregular grains enclosing 

 felspars but themselves moulded by augite. Also enclosed 

 in olivine and augite are a few octahedra of magnetite, 

 but most of the iron ore of the rock has the irregular habit 

 of ilmenite. 



There is much apatite in thin needles of a faint but 

 decided greenish tint. This is enclosed in all the felspars, 

 but not a single example of its inclusion in L olivine was 

 noted. The abundant chlorite is distributed in such a way 

 as to suggest the infilling of numerous microlitic spaces. 

 There is a good deal of zeolite filling small irregular spaces. 

 It is of two kinds, (i.) cloudy brown almost opaque material 

 which is indeterminate, and (ii.) a clear fibrous mineral 

 answering to stilbite. 



Quartz syenite, Mwmbilla-Engelburg Road. — Hypidio- 

 morphic granular rock of rather variable grainsize. The 

 most abundant mineral is anorthoclase in prismatic sections. 

 It is perfectly fresh and is simple, shows twinning after 



