Fig. 10 Photomicrograph of thin section of Oriskan}- sandstone, taken 

 with nicols crossed, magnification 65 diameters, showing 



a Original rounded grains with trains of inclusions terminating at original 

 grain margins 



b Secondary growth of clear quartz in parallel orientation 



c Size of grains and slight interlocking habit ; this poorly interlocking 

 habit makes the rock susceptible to ready disaggregation where exposed to 

 weathering action. 



