of the ferro-magnesian minerals : biotite, hornblende, augite and enstatite. 

 Thus we have such varieties as quartz-biotite-felsites and -trachytes ; quartz 

 hornblende-felsites and -trachytes, &c., &c. 



APPENDIX TO GROUP C. 

 The general remarks made with reference to Group B apply also here. 



GROUP 



ROCKS CONTAINING NEPHELINE OR LEUCITE ; SOMETIMES NEPHELIXE AND 



LEUCITE. 



(a) With orthoclase, anorthoclase or microcline. 

 (a) Granitic texture. 



Elceolite- or nepheline-syenitc. (2) 

 (6) Trachytic texture. 



(1) With nepheline and sanidine. Nephelinc-phonolite or 



phonolite proper, 



(2) "With leucite and sanidine. Leucite-phonolite. 



(3) "With leucite, nepheline and sanidine. Leucitophyre 



(Rosenbuscli). 

 (ft) With platjiodase. 



(1) With nepheline. Nephettne-tephrite (Rosenbuscli). 



(2) With leucite. Leucite-tephrite. 



(3) With leucite and nepheline. Leucite-nepheline-ieplirite. 

 (7) Without felspar. 



(1) With nepheline ; without olivine. Nephelinite 



(Rosenlusch). 



(2) With leucite ; without olivine. Leucitite (Rosenbusch). 



(3) With nepheline and olivine. Neplielinc-basaU. 



(4) With leucite and olivine. Leucite-lasah. 



(1) Rocks of this group are rich in accessory minerals nosean, melanite, sodalite, melilite, 

 &c., and many varieties not represented in the above scheme are accordingly recognised. It is 

 represented in Britain, so far as we know at present, by the solitary example of the Phonolite of 

 the Wolf Rock. 



(2) Miascite, ditroite and foyaite are varieties of nepheline-syenite. 



