FOLIATION IN THE PRE-CAMBRIAN OF NEW YORK 600 



such process as that outlined above. Barlow, describing the granite 

 of central Ontario, says: "The movements .... continued as 

 the rock cooled and while it was filled with abundant products 

 of crystallization, the movements being brought to a close only by 

 the complete solidification of the rock. Evidence of protoclastic 

 structure can, therefore, be seen throughout all the areas colored 

 as granite or granite-gneiss on the map." 1 



Teall says, regarding the granite of the county of Kircudbright: 

 "The quartz and alkali feldspar, which .... were the last con- 

 stituents to solidify, are those which have yielded most to the 



deforming stresses. They show signs of crushing It is 



probable that the pressure acted before the rock mass had actually 

 cooled." 2 



McMahon, discussing the gneissic granite of the Himalayas, 

 says: "It is no argument against the idea of the development of 

 foliation before final consolidation of the granite to point to evidence 

 of strain and mechanical action in the rock; for the existence of 

 strain and mechanical action during the critical period in the history 

 of the granite is an essential part of the theory itself." 3 He admits 

 that the granite has been subjected to lateral pressure but says 

 that this does not prove the foliation to have been produced by such 

 pressure. 



Weinschenk, 4 explaining certain schistose Alpine granites, sug- 

 gests that, in a somewhat advanced stage of magma consolidation, 

 a crystalline skeleton is formed whose interstices are filled with 

 liquid magma. Movements cause crushing of the skeleton, 

 breaking the feldspars and bending the mica plates. Quartz, 

 the last mineral to crystallize, is flattened out but not much 

 broken. 



According to Trueman: "It seems not illogical to assume that 

 the movements which were, apparently, present late in the period 

 of consolidation should have sometimes been continued after por- 

 tions or the whole of the rock had completely solidified. If such 



1 A. E. Barlow, Geol. Surv. Can., Mem. 57, 1915, p. 48. 



2 J. J. H. Teall, Mem. Geol. Surv. Great Britain, Expl. Sheet 5, 1896, p. 43. 



3 C. A. McMahon, Geol. Mag., N.S., Decade 4, IV (1897), 347. 



4 E. Weinschenk, Congres geol. inter., Compte rendu, Session VIII, 1 (1900), 341. 



