72 



appeared to be in a fairly undecomposed condition, for in 

 most other localities weathering has deformed the rock both 

 mechanically and chemically. 



Result, 



j of Analy 



sis. 



The Norm. 





I. 



II. 



Quartz 



.. 552 



Si0 2 ... 



53-18 



53-11 



Orthoclase . . . 



3-89 



A1 2 3 ... 



1761 



15-55 



Albite 



.. 17-29 



Fe 2 3 ... 



1-59 



1-26 



Anorthite 



.. 36-97 



FeO ... 



6-47 



7-17 



Diopside 



.. 12-17 



MgO ... 



6-59 



6-50 



Hypersthene 



.. 1996 



CaO ... 



10*42 



8-93 



Magnetite 



232 



Na 2 ... 



2-03 



303 



Ilmenite 



1-52 



K 2 ... 



•70 



•28 



Water 



•73 



H 2 + 



•40 



3-12 









H 2 0- 



•33 



•04 





100-37 



C0 2 ... 



trace 



•32 







Ti0 2 ... 



•78 



•40 







P 2 5 ... 



trace 



— 







S0 3 ... 



nil 



— 







s 



trace 



0-4 



* 





Cr 2 3 ... 



trace 



— 







NiO, CoO 



trace 



— 







MnO ... 



•10 



•59 







BaO . . . 



•13 W 



— 







SrO ... 



•02 (6) 



— 







Fe 



100-35 



•03 

 100-37 







Sp. Gr. 2-88. Sp. Or. 291 



I. Enstatite basalt, Kangaroo Island, S.A. 

 II. Augite andesite (altered). Summit of Mount 

 Anketel, West Pilbarra Goldfield. (Geol. Sur., 

 W.A., Bull., No. 33, p. 148.) (Fe=03.) 



Classification. 

 Class III. Order 5. Rang 4. Subrang 3. 

 Magmatic name, Auvergnose. 



Notes on the Analysis. 

 The rock is particularly interesting in that it is high 

 in silica and alumina, thus accounting for the presence of 

 abnormative minerals. It will be seen that quartz is present 

 in the norm and is completely absent in the mode. Since the 

 American classification does not take into account whether a 

 mineral is crystalline or glassy it is probable that the excess 



(6) Not determined spectroscopically. 



