PROBLEMS OF PETROGRAPHIC CLASSIFICATION 



795 



Table I gives the actual analyses of the Kotakarra (I) and Boirani 

 (II) rocks; the calculated chemical composition corresponding to 

 the estimated original mineral constitution (la and Ila); and the 

 calculated composition of the garnets in rocks I and II, supposed 

 to fairly represent certain garnet rocks of Kotakarra and Boirani 

 (III and IV) . In Table II the norms calculated by Termor from 

 la, 11a, III, and IV are also quoted. 



TABLE I 

 Actual and Calculated Analyses 



* Combined 8102=33.50: free SiO, =18.65. 



t Combined Si02=32 .25: free SiOj =28.35. 



ft Calculated from fluorine assumed in apatite. 



A rock having the composition of la would be, as Termor has 

 shown, a perpotassic andase in the Quantitative System (II. 5. 3. i) ; 

 one like Ila would be a perpotassic monzonase (II. 5. 2. i). No 

 perpotassic rock of either of these rangs has been described pre- 

 viously and Termor proposes the names kodurose and boiranose, 

 which cannot be accepted, as shown below. 



The further quantitative classification of la on the basis of 

 the amount and chemical character of the femic constituents is 

 carried out by Termor in accord with the principles of the system. 



