122 ^Transactions of the Royal Society of Victoria. 



process has also eliminated iron ore. The greater part of 

 the rock is composed of quartz grains, which have been 

 crystallised last of all. 



The subjoined analysis is of this sample : — 



Analysis No. 8. 



P2O5 06 



SiOg ... ... ... 69-79 



AI.2O3 ... ... ... 16-47 



Fe.gOa ••• ••• ••• '53 



Fe.O ... ... .. 2-97 



Ca.O ... .' -73 



Mg.O ... ... ... 1-95 



K2O ... ... ... 3-44 



Na-aO ... ... ... 1-68 



H2O -99 



98-61 



Hygroscopic Moisture ... "49 



Sp.gr. ... ... ... 2-720 



Close adjoining this rock is the boundary of the granites, 

 which are porphyritic with orthoclase felspars. A sample 

 which I collected close to the boundary is a light-coloured 

 crystalline granular rock, of medium texture, containing two 

 micas, felspars, and quartz, and with porphyritic crystals of 

 rather greasy-looking orthoclase. 



A quantitative analysis of this sample is as follows : — 



Analysis No. 9. — Granite. 



P2O5 ... ... ... -05 



SLOg ... ... ... 68-87 ^ 



AlA ... ... ... 16-62 



Fe.203 ... ... ... -43 



Fe.O ... ... ... 2-72 



Ca.O ... ... ... '71 



Mg.O ... ... ... 1-60 



K2O ... ... ... 6-48 



Na.20 ... ... ... 1-80 



H2O -74 



100-02 



Hygroscopic Moisture ... '21 



Sp.gr. ... ... ... 2-762 



