Fig. 4. Felsic diorite remnant layer (~0.5 m thick; left side under knife and at bottom left) in megacrystal Twentynine Palms quartz monzonite in Bartlett Mountains northwest of Joshua Tree, California (Fig. 2). On right side of image, loose K-feldspar megacrysts have slid down an eroded slope of quartz monzonite (more than 100 m high) to cover portions of the felsic diorite layer.