hy their Chemical Composition. 



133 



16 LIMBURGITE. 



15 LEUCITITE. 



\J \A PICRITE. 



13 GABBRO. 



12 BASALT. 



11 TEPHRITE. 



10 DOLERITE. 



9 DIORITE. 



O AVERAGE. 



8 NORITE. 



7 PHONOLITE. 



6 ANDESITE. 



5 TRACHYTE. 



4 GRANO-DIORITE. 



3 GRANITE. 



2 GRANITITE. 



_' 1 RHYOLITE. 



-•SWa- f I I I I I , ■-.— t 



