CLASSIFICATION OF THE PLUTONIC ROCKS 259 



The affinities of the various members of a continuous series 

 or of members of different series in the same group, are also 



H 3 



> m 

 o 



O 03 



H 



Eh 



a 

 o 

 -d 

 u 

 o 

 © 



o 



CaO -171 



K 2 0+Na 2 «139 



Al z 03 '136 

 MgO -129 



Na 2 -091 



K 2 -048 

 FeO -041 



•H C^ 

 CO ' 



o 



o 



e> 



o 



w 



E-« 



M 

 > 



o 

 a 



a 



H M 



M U 

 'Z <0 



><< 

 CO 



• w 



S u 



•209 



•19 



•128 



■062 



•04 

 •034 



•02 



Fig. 6. — Diagram of the Molecular Proportions of the Nepheline Series. 



well brought out by Brogger's figures. Exigencies of space 

 prohibit the comparison of a large number of these figures ; but 

 it will suffice to trace their variation through the chief members 



