234 



The analyses, norms calculated therefrom, and position 

 in the American classification of these two rocks are given 

 below : — 



Ay 



'ALYSES. 





Calculated 



Norms 







A. 



B. 





A. 



B. 



Si 0., ... 



49-29 



50'63 



Orthoclase 



12-23 



10-01 



A1,0, ... 



18-81 



16-30 



Albite 



26-20 



27-25 



Fe, O3... 



3-57 



5-34* 



Anorthite 



31-14 



25-20 



FeO ... 



7-78 



6-46 



Diopside 



10-87 



9-53 



MgO .. 



3-28 



6-62 



Hypersthene ... 



8-34 



14-46 



CaO ... 



9-25 



7-65 



1 Olivine ... 



3-13 



4-58 



IsXO ... 



3-07 



3-22 



Magnetite 



4-10 



7-66 



KoO ... 



2-10 



1-69 



Ilmenite 



5-34 



1-52 



H3O + 



1-07 



-89 



Water 



1-27 



103 



H,0 - 



-20 



-14 









TiO, ... 



2-17 



-80 









CO, ... 



trace 



nil 









SrO ... 



n.a. 



trace 











100-59 



99-74 



102-62 



101-24 



* This high figure is due to the rock being somewhat oxidized, 



considerable hsematite being present in it. 



Classification. 



A. II. 5. 3. 3. 

 Magmatic name — Shonshonose, near Andose. 



B. II. 5. 3. 4. 

 Magmatic name — Andose. 



These analyses show percentages of Ti Oo which are in 

 no way abnormal for diabases, and it cannot then be as- 

 sumed that the Blinnian intrusions have any genetic connec- 

 tion with the South Australian titaniferous magma, whose 

 existence is proved chiefly by its Pre-Cambrian develop- 

 ments. <=' The alkali content of the Blinman diabases is, 

 however, slightly greater than usual. The wide variation 

 in the magnesia content is very striking. 



With regard to the minor and undetermined constituents 

 a few remarks may be made. Manganese must be present 

 only in very small amount, judging from the pale-green of 

 the soda carbonate melt. Phosphorus is very low, as no 

 apatite was seen microscopically. Chlorine, present in the 

 scapolite of (B), will occur in but small amount. As there 

 is scarcely 1 per cent, of this mineral, there cannot be more 

 than '03 per cent, of chlorine from this source. The most 



(5) This volume, p. 101. 



