fig. I 



Lean ore, Cole mine, showing large, irregular masses of pyrite in the fine- 

 grained rock. (9/10 natural size) 



Fig. 2 Photomicrograph of schistose wall-rock, Cole mine, with pyrite developed 



in a chlorite vein and, to a less extent, throughout the rock. The white mineral is 



almost entirely quartz. Some cataclastic structure is shown. (Magnified 27.5 

 diameters) 



