OLIVINE-BEARING QUARTZ-MONZONITE FROM KIANDRA. 267 
to start separating, followed by biotite, then came ortho- 
clase and quartz, in part at all events simultaneously. A 
little iron ore is embedded in pyroxene and plagioclase, but 
apatite seems to have remained in solution until the plagio- 
clase had ceased to crystallize. 
The rock which is referred to by Mr. Andrews in his 
Kiandra report as a norite is in many respects similar to: 
the quartz-monzonite just described. In hand specimen it 
is darker in colour and has a porphyritic instead of a 
granular appearance. The qualitative mineral constitution 
is the same as that of the quartz-monzonite, and so are the 
internal characteristics of most of the constituent minerals,. 
but the texture is different. Pyroxene occurs in two 
generations, and the same remark applies to the plagioclase,. 
so that the rock has almost a porphyritic, or as Mr. Card 
suggests, a lamprophyric appearance. ‘There are pyrox- 
enes, both augite and clino-hypersthene, in crystals up to 
> mm. long, embedded in a groundmass of stout plagioclase: 
prisms averaging about ‘7 mm., the interstices between 
these being filled with quartz, or orthoclase, or more com-- 
monly with an aggregate of tiny plagioclase, pyroxene, 
magnetite and apatite crystals with interstitial quartz or 
orthoclase, or both. 
Some conception of the relative development of the 
principal constituents may be obtained from the following 
results of a very rough Rosiwal measurement, the figures. 
representing volume percentages :— 
Pyroxene phenocrysts ae See ae seo) el 
Groundmass pyroxene aes ine ap rennet 
Biotite oh Nee ee ie sr a ae 
Magnetite ... ae nee he re Ane Qa | 
Plagioclase, with orthoclase, quartz, and apatite 65°1 

100°0 
