BY W. H. CLEMES, B.A.. B.SC. li> 



constituents are very few. Running through the boulders 

 oil the sides of Mt. Hazard ai'e to be found narrow veins 

 of microgranite, a very fine-grained variety composed of 

 felspar, biotite and quartz. On the northern side of the 

 bay also occurred a highly poi-phyritic granite with large 

 crystals of felspar (orthoelase?), also quartz, biotite and 

 muscovite. 



Numerous quartz veins traversed the rock in a more or 

 less north and south direction, and varied considerably in 

 size. They varied also in colour from rose to white, and 

 there were numerous nests of rock crystals. There was 

 no evidence of the greisenised zone, carr^ung tin, found at 

 the northern end of Schouten Main. 



At intervals along the south side of the bay are 

 parallel dykes of dark rock, running approximately north 

 and south. This rock has previously been referred to by 

 Dr. Milligan, who thought that it was greenstone, and 

 certainly it somewhat resembles diabase or dolerite to the 

 naked eye. But microseopically it is resolvable into a 

 combination of plagioclase, felspar, and hornblende, and 

 is therefore a diorite. Some biotite is also present. The 

 felspars in lath-shapecl sections exhibit both albite and 

 Carlsbad twinning, and trom the eixtinction angles belong 

 to the O'ligoclase-andesine series. The biotite where not 

 chloritised is brown m colour. The hornblende is irregu- 

 lar in form and green. It is mostly chloritised to some ex- 

 tent, during which process iron oxide has separated out 

 abundantly. Diorite is a rock which is met with in more 

 than one form of occurrence. It may exist in dyke form, 

 or as' a separate rock mass, or finally as a facies of granite. 

 The structure of the present rock is consonant with its 

 occurrence either as a faeies or a dyke. Evidently it has 

 genetic connection with the granite rock of Freycinet 

 Peninsula. In O'ne vein close to the water's edge large 

 crystals of felspar were to be seen embedded in the diorite, 

 whicn there appeared raoie grey in colour. I was not able 

 to examine it closer owing to its position and the lack of 

 time, but it appeared as if seme absorption of the con- 

 stituents of the granite had taken jDlace. leading one al- 

 most to suppose that the dyke theory was more probable, 

 but there is not sufficient data to dogmatise about the mat- 

 ter. They certainly appear to be xen,ocrysts rather than 

 phenocrysts. 



Most of the hills appear as great boss-like masses with 

 rounded surfaces, curiously streaked by the deseending 

 waters charged with mineral matter. These hills descend 

 right into the sea. with little or no foreshore. Along the 



