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



Granophyre, near base of Mount A] ford on the northern 

 side. — The rock is granophyric with pseudo-porphyritic 

 nuclei of quartz, orthoclase, anorthoclase(?), aud haematite. 

 Individual grains of the various minerals are up to 4 mm. 

 diameter, but mostly are much smaller. Haematite is 

 always enclosed in the other minerals and probably repre- 

 sents the alteration product of original magnetite. Felspar 

 is considerably kaolinized. Some is definite orthoclase, but 

 some appears to have higher refractive index and shows 

 very fine and hazy albite twinning. Sometimes quartz, 

 sometimes felspar forms the nucleus round which a grano- 

 phyric intergrowth is formed. 



Mount Alford. — There is a marked variation in texture 

 within the limits of the microscope slide but the line of 

 demarcation is not very sharply drawn. 



The finer grained portion is cryptocrystalline and spheru- 

 litic with occasional granophyric patches, very much 

 clouded by decomposition products. There are occasional 

 phenocrysts of plagioclase, and grains of magnetite up to 

 0*5 mm. diameter. 



The coarser portion has a fine base composed of untwinned 

 felspar (orthoclase ?), with a little quartz, chlorite and 

 magnetite and very little trace of granophyric structure. 

 In this part occur abundant plagioclase phenocrysts and 

 grains of titaniferous magnetite very irregular in shape 

 and much intergrown with the ferromagnesian constituent. 

 The latter is represented by green fibrous uralite. 



The plagioclase phenocrysts appear to be the same in 

 both portions. They are idiomorphic, twinned after albite 

 and Carlsbad laws mostly, with occasional patches showing 

 pericline lamellae, and must be referred to acid labradorite. 



In the coarser portion there occur, fairly abundantly, 

 rounded grains of quartz and also one little nest of quartz 



