NOTES ON SOME IGNEOUS ROCKS OF JAPAN 



559 



From these figures the formula of the anorthoclase is found to 

 be Ora.jgAbjAri!. 



The analysis of the rock, by K. Takayanagi, and that of the 

 pantelleritic trachyte, by Fornstner, are given in the following 

 table : 



Si0 2 



A1 2 3 



Fe 2 3 



FeO 



MgO 



CaO 



Na 2 '. 5 . 60 



K 2 4.16 



H 2 0* 0.87 



Ti0 2 0.66 



P2O5 o. 29 



MnO 0.48 



A 

 62.36 



17-95 

 i-5S 

 2.62 



o. 72 

 2-75 



B 

 61.43 



Si 

 II 



30 



54 

 45 

 22 



95 



100. 10 99. 51 



* Loss on ignition. 



A = Soda-trachyte, Matsu-shima, Kyushu. 



B=Augite-andesite (pantelleritic trachyte of Rosenbusch), Porto Scauri, Pantelleria. 



The norms, calculated from these analyses, are as follows: 



Quartz 6.1 



Orthoclase 25.0 



Albite 47 . 2 



Anorthite 1 1 • 4 



Diopside 0.7 



Hypersthene 4.6 



Magnetite 2.3 



Ilmenite 1.4 



Apatite 0.6 



B 



5-o 



23- 



99-3 



Ratios from the norms are given below: 



Sal 

 Fem 



Q = 



F 



K 2 0'+Na 2 0' 



CaO' 

 K 2 0^_ 

 Na 2 /_ 



A 

 •9-25 



.0.07 



•3- 29 



.0.50 



8.31 

 0.06 

 4.90 

 0.42 



