554 . WALDEMAR LINDGREN 
composition of a schist tends to approach the distinctive chemical 
characteristics of the dominant platy or columnar mineral, be it 
muscovite, chlorite, or amphibole. This is clearly the result of a. 
slow metasomatic action, though this view is not definitely expressed 
by the authors, and if true indicates that gradual exchange of 
material cannot be excluded for the crystalline schists. 
It is well to recognize that recrystallization in rocks under 
stress remains a subject beset with many difficulties and uncer- 
tainties. Fully conscious of this I advance the foregoing sugges- 
tions simply as a tentative effort from the viewpoint of a student of 
metasomatic action. © 
