GeoUxjy of Cobury Area. 

 A chemical analysis of the rock is : — 



l«1 



100.53 



100.4: 



A. Rock from basalt pavement in bed of Merri, East of Pentridge. G. A. 

 -Cook. 



B. Fine grained basalt, C4reensborongh. N. R. Junner. Proe. Roy. Soc. 

 Victoria, 1913, p. 335. 



C. Older basalt, A quarry, Tiillamaiine. F. L. Stillwell. Proc, Roy. Sec. 

 Victoria, 1911, p. 165. 



Analyses B and C are given for purposes of comparison. 

 Following the method of the American classification of rocks, the 

 norm, of the rock from Coburg was calculated. 

 It is: — 



Orthoelase 



A 1 bite 



Anorthite- 



Corunduni 



Hypersthene 



Olivine 



Magnetite 



Jlmenite - 



Apatite 



Percentage. 



6.0 

 21.2 

 38.6 



2.9 

 21.8 



2.5 



4.0 



2.9 



0.20 



100.0 



