Victoridu Igneous Rocks. 



26^ 



rocks taken as abscissae, and tlie percentages of the other constitu- 

 ents as ordinates. Such a variation diagram was constructed, based 

 on the analyses of tlie Macedon granodiorite-dacite series, and is 

 given in Fig. 1. 



r 2 5 4 S 6 7 8 9 10 II 12 15 14 15 16 



Fig. 1, 



