A. Holmes — Classification of Igneous Rocks. 



127 



UNDEESATUEATED E0CK8 : CHAEACTEEIZED BY FELSPATHOIDS AND 



OLIVINE. 



Or Soda Or^.s Eocks. Or 3 7.s Soda-potash Eocks. Or 62 .s Potash Or 8 7.s Eocks. Orioo 



