MAGNETITE GARNET ROCKS COUL80N. 



297 



The analysed specimens belong to the second group, and Tables VI and VII 

 give the molecular percentages of the constituent oxides, the group values and the 

 projection values according to Ozann's scheme.* 



TABLE VI. 



TABLE VII. 



Group and Projcc- 



I. 



II. 



III. IV. 



I. No. 149, Magnetite-garnet-gneiss. 

 II. No. 181, Porphyroblastic magnetite-garnet-gneias. 



III. No. 102, Garnct-quartz-magnetite rock. 



IV. No. 348, Garnet-inagnetite-schist. 



V. Mean values of Grubenmann's Xltli Group. 



The values for No. 149 have been obtained from the Rosiwal analysis in Table I 

 on the assumption that biotite has the composition K 2 FeAl 2 (Si0 4 ) 3 , that the garnet is 

 almandine and that quartz, orthoclase, and labradorite are present in equal proportion 8 



Orubenmann, op cit., 1910, pp. 134-6. 



