Fig. 2. Connected, non-rotated blocks of dark pinkish-brown porphyritic quartz monzonite, penetrated and replaced by light-gray micro-quartz monzonite. The penetration occurs above and below the blocks along nearly horizontal planes as well as along nearly vertical lobate zones extending into or through the blocks. Picture is of an outcrop in the west wall of the Gibson Arroyo channel in Ajo, Arizona, at the west end of Rocalla Road where this road bends and makes a transition to the north end of the Scenic Loop Road.