6o4 



CLARENCE N. FENNER 



It was observed in many instances that in such occurrences 

 as show bands of basic rock in largest amount the adjacent 

 granite contains the greatest quantity of dark sihcates, and 

 where inclusions are rare the granite is very light colored and 

 nearly free from ferromagnesian minerals, and it seems probable 

 that the invading magma was composed essentially of quartz 

 and feldspars, and that the dark minerals, even in massive 



granite, were derived to a large degree from the rocks which 

 were invaded. 



In the foliated gneisses the light bands are frequently of the same 

 composition and appearance as the granite of the large masses, 

 and their relations to such bodies and their general characteristics 

 are such as to point strongly to their being essentially portions of the 

 same magma which have traveled long distances along parallel 

 layers of inclosing rock. The mechanism of injection appears to 

 have involved a progressive movement of a rather thin magma 

 between the layers of a foliated rock, in some cases spreading them 



