REPORT OF THE DIRECTOR I917 107 



selves crossed by this foliation. Yet when examined in thin section 

 these do not show evidences either of crushing or of recrystallization. 

 They have a normal granitoid texture — the usual result of crys- 

 tallization from a magma. Furthermore, if this massive gneiss is 

 not the result of recrystallization (an hypothesis which it is believed 

 the facts do not support), then the foliation of the veins likewise 

 can not be due to this cause. The statement that the degree of 

 crushing of both dikes and country rock is the same also holds for 

 those dikes which are crossed by the foliation of the intruded gneisses. 

 The assumption that the foliation was induced in the dikes before 

 either the country rock or the dike was completely solidified neces- 

 sitates a close genetic connection between the igneous gneisses and 

 the dikes or pegmatite veins. This, however, was exactly the 

 conclusion arrived at from other data before the foregoing theory 

 was considered. It is noteworthy that field evidence indicates that 

 the Diana mass was in a much more advanced state of consolidation 

 than the Croghan mass at the time of intrusion of the hyperite 

 dikes. Thus in the rocks of the Diana mass the hyperite usually 

 occurs in well-defined dikes, whereas in many cases in the rocks of 

 the Croghan body masses of hyperite and gabbro interfinger so 

 with the granite and syenite that it is utterly impossible to tell 

 which is country rock and which is intrusive. Evidently both 

 masses were in at least a semifluid state and squeezed into each 



other. 



That it is possible to have a foliation induced in a rock while it 

 is still in a fluid or semiviscous state is well exemplified in a band 

 of gneiss northwest of Lake Bonaparte. Here Grenville gneiss has 

 been thoroughly injected and almost completely disintegrated by 

 pegmatite. In those remnants of gneiss which retain their individu- 

 ality, the biotite flakes and quartz are oriented parallel to the 

 banding (plate 6, upper figure), but in the pegmatitic material, the 

 quartz and feldspar are all oriented at right angles to the banding 

 and hence to that portion of the biotite and quartz which has 

 retained the structure of the gneiss (plate 6, lower figure). Thus 

 we have two foliations at right angles to each other in the same 

 rock, one written over the other without completely destroying it — 

 a palimpsest. The quartz of the pegmatite is wholly uncrushed and 

 assuredly would not have been oriented by recrystallization at right 

 angles to the biotite. On the contrary, it is interpreted as a folia- 

 tion of protoclastic origin. This type of phenomenon also shows 

 up in specimens from several localities where belts are oriented 

 at an angle to the direction of the orogenic forces, 



