Plate i8 







f? 





V*-t ■ 



■- vAa 



>.<->? 



Photomicrograph of no.. 187-6. Storm King granite. Taken with plain light, magnification 

 about 30 diameters. 



Taken to show the distribution of ferro-magnesian minerals in the rock and the development of 

 perthitic habit. 



The minerals are: Quartz (clear), perthitic feldspar, hornblende (dark rough grains), biotite 

 (dark smooth flakes) . 



Plate 19 



Photomicrograph of no. \?ii-h-x. Storm King granite. Taken with crossed nicols, magnification 

 about 30 diameters. 



A different field of the same slide as the previous one taken with crossed nicols to show better the 

 micro-structure of the rock, especially the microperthite habit and microline and the strained 

 condition. 



The minerals are quartz, perthite, acid plagioclase, microcline, hornblende and zircon. 



