494 



THOMAS T. RE/' 



original with the dike matter, why it appears in depth and not 

 at the surface is a question that I am not prepared to answer. 



Between these areas is a band of biotite schist which presents 

 an unusually fine example of the stringing out and plication of 

 quartz lenses. At times a single lens wi'l have been squeezed 

 to a band scarcely an inch thick and folded on itself from a 

 dozen to twenty times, the folds being several inches to several 



P'iG. I. — Plication of quartz vein in schist. 



feet long and sometimes only a fraction of an inch across. The 

 white quartz against the dark background of the schist presents 

 a most striking appearance. This is shown by the accompany- 

 ing photograph ( Fig. i ) . The size of the specimen can be judged 

 from the volume of the Neiies Jalirbiich which is used to prop it 

 up. In a width of about six inches we have twelve folds, so 

 that the same band appears twenty-four times. It seems most 

 probable that in this case the quartz must have existed as a vein 

 in the rock before its metamorphism, and the oscillations which 

 took place during the metamorphic processes have produced 



