pyroxene. Rhombic pyroxene is subordinate to monoclinic 

 pyroxene and both may contain pleonaste. In some cases 

 this forms excessively fine granophyric intergrowth, at 

 other times rather more coarse. The felspar is labradorite. 



J- 



liKMiriiiir to t'onn sfj'|H'iiiiiie and talc (?) along the cracks: 

 from the almost complete absence of magnetite it must be 

 nearly pure magnesium olivine. Of the pyroxenes, diopside 

 and enstatite are present, the latter in considerable 

 amount, occasionally forming a large plate, in which 

 diopside and olivine are set poikilitically. Pleonaste forms 

 granophyric intergrowths occurring both in diopside and 

 enstatite. If, however, there should be the two pyroxenes 

 side by side, and pleonaste in one only of them, it will 

 usually be enstatite. With the diopside there is developed 

 the curious feature of a large lump of pleonaste outside the 

 grain sending apophyses into the grain which terminate in 

 a granophyric intergrowth, the distal ends run perpendicular 

 to the bounding surface of the diopside against the plagio- 

 clase. In one instance, and the only one in the series of 

 slides studied, the granophyric intergrowth spreads radially 

 from a point within a pyroxene grain. The plagioclase is 

 labradorite. 



There is one rock which though perhaps not truly plutonic 

 may best be considered here as it shows to perfection the 

 granophyric intergrowth of pleonaste and pyroxene. Macro- 

 scopically it was noticeable as being of small grain size, 

 and containing a large crystal of diallage, two centimetres 

 in diameter (the source of the diallap' -tu<iiV,| in detail). 

 Microscopically the texture is distinctly porphyritic, the 

 phenocrysts being slightly titaniferous augite, hypersthene 

 and labradorite. The pyroxenes are commencing to alter 

 the augite to chlorite and amphibole, the hypersthene to 



