NOTES ON SOME IGNEOUS ROCKS OF JAPAN 637 



CaO 7.84 



Na 2 1 . 44 



K 2 o. 79 



H 2 n.d. 



Ti0 2 0.42 



P 2 O s 0.13 



MnO 0.55 



100.78 



The norm, calculated from the above figures, is given below: 



Quartz 25. 1 



Orthoclase 5.0 



Albite 12. 1 



Anorthite 36. 1 



Diopside 2.1 



Hypersthene 13.6 



Magnetite 4.9 



Ilmenite 0.8 



99-7 



The ratios are: 



Sal 



3-66 



Fern 



Q 



— 047 



F 



K 2 0'+Na 2 0' 



0.25 



CaO' 



K 2 0' 



Q-39 



Na 2 0' 



By the Quantitative System the rock would be classified under 

 the name bandose. 



In this classification, it may be noted that the rock is charac- 

 terized by a high percentage of lime, which appears mostly as 

 modal anorthite, and by the comparatively high silica content. 



Generally speaking, the mineralogical and chemical characters 

 of the latest lava of Tarumai volcano seem to be representative of 



