214 HAROLD L. ALLING 
THERMO-EQUILIBRIUM DIAGRAM 
OF THE 
PLAGIOCLASE FELDSPARS 
(Ame |): 
AP ames | |: 
aR ey See |: 
Sh == Ln 
AB OLIG AWD LAB BYT AN 
Fic. 2.—Thermo-equilibrium diagram of the plagioclase feldspars, based upon a 
molecular percentage (after Bowen) 
