120 Transactions of the Royal Society of Victoria. 



A quantitative analysis which I made of this rock is 

 given below : — 



Af^ALYSIS No. 7 



.—Graphic Geanite. 



Si.02 



70-91 



ALA •- 



15-32 



Fe.A ... 



tr. 



Ca.O 



•58 



Mg.O 



07 



K2O 



10-07 



Na.20 



2-31 



H2O 



•51 





99-77 



Hygroscopic Moisture ... '15 



Sp.gr. ... ... ... 2-564 



[n.) Here are massive crystalline gTanular rocks with 

 aplite veins. A strong dyke of this rock traverses them, 

 dipping probably N. 20° E. about 40°. A hand sample from 

 this place is very fine grained and siliceous, and has no 

 resemblance to the thick-bedded schists which I have 

 described at (i) These rocks resemble some of the crystal- 

 line granular parts of the bedded schists, but are themselves 

 only faintly schistose in places ; whilst in others there are 

 crystalline granular patches of small size, whose composition 

 of felspar and quartz, with but little muscovite, approximates 

 in appearance to aplite, while it shades off also into the 

 surrounding rock. I must leave for future determination 

 the exact relations of these rocks to the schists on the one 

 hand, and to the intrusive granites at no great distance on 

 the other ; but I may point out that it may be possible that 

 we have here an instance in which the sediments under the 

 influence of the exudations from the plutonic magma have 

 more or less, in re-crystallising, assumed their character. I 

 have long since seen, and have pointed out, that large masses 

 of the lower parts of the Silurian sediments must have been 

 absorbed by the plutonic magmas. 



(o.) From {n) to this point there are but few rocks visible^ 

 and they are alj of a massive appearance. A sample collected 

 at (0) proved, on examination as a thin slice, to be 

 interesting. There is in it a ground mass, which is formed 

 in places of orthoclase felspar, which surrounds and includes 

 rounded or sub-angular grains of quartz, and this is. 



