46 



AUSTRALASIAN ANTARCTIC EXPEDITION. 

 Projection Values after Ozann. 



a = 



c = 



f 



20A 



A + C + F 



200 



A + C + F 



20F 



No. 153. 

 2-7 



3-6 

 13-7 



No. 629. 

 1-4 



3-1 

 15-5 



A + C + F 



Examination of these group values enables one to place both rocks among the 

 eclogites and amphibolites of Group IV. No. 629 is a typical amphibolite not far 

 removed from the mean group value. No. 153 approaches the plagioclase gneisses of 



f 



^VNAAAAAA 



VWYWVV 



AAAA/WV 





AAAAAAAA/V\IA/WVWV\AA 

 a c 



Fig. 4. 



3. Mean Value of Group III., the Plagioclase Gneisses. 



4. Mean Value of Group IV., the Eclogites and Amphibolites. 

 153. Epidote Biotite Schist, Cape Denison. 



629. Amphibolite, Cape Denison. 



Group III., and the group values S and M actually fall within the variation limits of 

 this group ; but, nevertheless, its position on the projection is much closer to the mean 

 position of Group IV. than to the mean position of Group III. Since both examples 

 fall into Group IV., we are able to assert that the whole suite of rocks considered falls 

 into the same group. 



In order to determine the subdivision of Group IV. it is necessary to recall the 

 microscopical characters. When we do so we find that the rocks do not wholly present 

 the characteristics of either the epi division or the meso division. In cases where the 



