Fig. 8 Photomicrograph of conglomeratic quartzite (Shawangunk) from 

 quarr}' near Accord; taken with nicols crossed, magnification 65 diameters. 

 Crushing, granulation, and silicification have destro3-ed grain outlines ; 

 especialh' well shown by the grain in the center of the field. Mill w^heels 

 (buhr stones) are made from this rock. Average grain diameter about 

 0.45 mm, disregarding the very large pebbles which are two or three centi- 

 meters in diameter, and occasionally larger. 



