108 C. H. GORDON — SYENITE-GNEISS (lEOPARD ROCK) FROM CANADA. 



men, shows this area to be made up of small angular and rounded grains 

 of microcline, between which in places there is a small amount of feld- 

 spar similar to that forming the microperthetic intergrowth observed in 

 the large microcline grains, and which is probably albite. Quartz appears 

 in irregular elongated grains here and there along the granular areas. It 

 has crystallized sharply against the adjoining constituents, fitting closely 

 into their sinuous outlines. Some grains are long and irregular in shape, 

 while others wliich a})pear similar are resolved in polarized light into 

 two or more grains having slightly difierent orientations. Rows of fluid 



FiGX'RE 5. — St'cliofi Ti aiisverse to {granular Bands in ihe coarse Syenite-gneiss. 



Showing augite crystal broken in the portion projecting into the granular band. Ait ^ augite ; 

 ^/ = microcline ; /* = plagioclase ; i? =- quartz ; /"= feldspar. 



inclusions frequently extend uninterruptedly from one quartz grain to 

 another, while in a few instances they were observed in direct continuity 

 with similar lines of inclusions in the adjoining microcline i)lates. 



The large microcline and augite grains, which constitute the larger 

 part of the section, are traversed in })laces by a series of irregular cracks, 

 which lie parallel with the lines of fluid inclusions in the quartz. 



The augite sometimes shows the effects of mechanical movements in 

 the fracturing and breaking of a grain lying in contact with the granular 

 zone. 



The grain shows fracturing throughout, but the breaking appears 



