Geology of Moorooduc. lf'3 



Quartz, Orthoclase, Biotite, Hornblende, Apa-tito. By Rosiwal's 

 method the volume proportions of the minerals are determined, 

 their proportions by weight calculated, and from a knowledge of 

 the chemical composition of each mineral the composition of the 

 rock is estimaited. The analysis supports the identification as 

 fjrano-diorite. Possible errors in the estimation of relative pro- 

 portions of the oxides of iron and magnesia, and in the relative 

 proportions of potash and soda are noted. Finally, a comparison 

 is instituted between the analysis so estimated and that of the 

 Grano-diorite from two miles north of Dandenong township. 



DESCRIPTION OF PLATES XIV.-XVI. 



Pr>ATK XIV. 



Geological sketch map of the Moorooduc district, reduced from 

 the Geological sketch map of tlie Mornington district, by 

 A. E. Kitson, F.G.S. 



Pl.mk XV. 



Upper figure. Grano-diorite, Mt. Eliza (No. 504) -f Xicols 

 X 17 diameteis. 



Lower figure. Metamorphic spotted Ordovician Slate, N. of 

 Moorooduc Railway Station (No. 506B), + Nicols. x 

 48 diameters.. H. L. Grayson, Photo-micro. 



Plate XVI. 

 Kev to plate XV. 

 Upper tigure. Q -= Quartz, Bi = Biotite, H = Hornblende, And = 



A°Klesine, Ab = Albiteand Albite-Oligoclase. 

 Lower tignre. M = Micaceous alteration product, Q = Quartz, 



bI= Biotite, M. A. = Mica aggregates. Hem = Hematite. 



