The north side of Mt. Pugh on Oct. 25, 2003. According to geologists: the rock to the left of the glacier, including the summit rocks, is gneissose quartz diorite (this is a light-gray rock with many quartz grains in it, or so it looked to me); the rock on the right is greenschist (a rock that always seems to be convoluted and haphazard in structure). The glacier itself lies along a fault line between these two rock types. This is the Straight Creek Fault.