210 Proceedings of the Royal Society of Victoria. 



laths of felspar and augite. In this are set crystals of sanidine, 

 augite, hornblende, and nepheline. The other minerals present 

 are apatite and sphene, with mica and grains of magnetite of 

 secondary origin. The sanidine occurs in tabular crystals, often 

 showing Carlsbad twinning with characteristic broken line of 

 penetration. Augite is present in large crystals with eroded 

 edges and dark zonal border, and also in groups or bunches of 

 small crystals with somewhat ill-defined boundaries. Horn- 

 blende has undergone considerable modification by magraatic 

 secretion ; the crystal form is as a rule well-preserved, but a dark 

 zonal border has in some cases been formed, leaving an internal 

 portion showing marked pleochroism, while in others the entire 

 crystal has been replaced. Nepheline is present in considerable 

 quantity, it occurs for the most part in microscopic forms giving 

 quadratic and hexagonal sections, but there are a few crystals of 

 large size visible. The other minerals in the slide do not call for 

 any detailed notice. 



An analysis of this rock kindly made for me by Messrs. W. H. 

 Green, B.Sc, and B. D. Steele, B.Sc, yielded the following 



Twenty-eight per cent, of the rock is soluble in strong HCl. 



This analysis completes the determination of the rock as a 

 phonolite; it is in close agreement with that of a phonolite from 

 Greenland Harbour given at page 134 of the Challenger volume. 



Greenland Harbour. — The single specimen from this place is 

 an augite-olivine rock approaching in type a limburgite. It has 

 a micro-granular base composed of grains of augite and magnetite, 

 with a small quantity of lath-shaped felspar microliths. No 

 phenocrysts of felspar occur ; the olivine crystals are numerous, 

 of large size, and have undergone much serpentinization ; there 

 are traces of secondary zeolitic matter. 



