60S WILLIAM J. MILLER 



pressure. This being the case, it is only necessary to consider that 

 there were movements in the slowly cooling and stiffening magma 

 whereby the minerals already crystallized out were more or less 

 broken and drawn out into a sort of rluidal arrangement parallel 

 to the foliation, while the minerals last to form were much less 

 granulated. A significant point in this connection is that, in rocks 

 which are definitely known to have been subjected to severe com- 

 pression, quartz is quite generally more granulated than feldspar. 

 Both Leith 1 and Loughlin- have emphasized this point. Now, in 

 the Adirondack intrusives. as we have shown, the feldspar is very 

 commonly distinctly more granulated than the quartz, and the 

 evidence is, therefore, opposed to deformation of the Adirondack 

 rocks by severe regional compression. 



The facts that degree of foliation and granulation often vary 

 markedly within a few feet or yards, and that the most perfectly 

 foliated portions are often also the most highly granulated, are to 

 be expected, because flowage in certain portions of the magma 

 during the late stage of consolidation would produce in those por- 

 tions not only good primary foliation but also notable crushing 

 of the already formed minerals by the movements in the stiff, 

 pasty magma. It seems impossible to explain satisfactorily such 

 marked differences in degree of both foliation and granulation in the 

 syenite-granite series except as the result of movements in the con- 

 gealing magma. In few cases, if any, is there evidence for shearing, 

 so that if compression of the region be assumed as the cause of the 

 foliation and granulation, it is impossible to explain why adjacent 

 zones often present such differences in degree of foliation and 

 granulation. 



Again, the general lack of notable granulation in the oldest 

 rocks of the region — the Grenville — is not compatible with the 

 idea of production of cataclastie structure in the intrusives by lateral 

 pressure, else why were the still older rocks also not proportionately 

 affected ? 



Other workers have presented strong evidence for the produc- 

 tion of a granulated or protoclastic texture in igneous rocks by some 



1 C. K. Leith, U.S. Geo!. Sun:, Bull. 239, 1905, pp. 33-34. 



2 G. F. Loughlin, ibid., Bull. 492, 1912, p. 12S. 



