622 F. F. GROUT GEAPHIC STUDY OF IGNEOUS ROCK SERIES 



15 



nepheute- 

 syenite 



<0 



* syenite 



quaitz- 

 monzonite 



• rhyolitc 



ranilc ai'iil 



© igneous 

 rock 



• basanite 



granojdiorite 



• diorite,. 



pegmatite 



basalt 

 anorthosite 



* quartz-diorite 



gabbro 



olivine gabbro 



• peridotite 



• pyroxemu- 



3 ZO 



DEFICIENCIES 



S/L/CA 



SO 40 



£ X.CESSSS 



FIGURE 1. — Distribution of standard Rock Families in a Diagram showing Alkalies 



and Silica 



The dotted outline shows the range of composition of the flows from the greater 



lava fields. 



