Fig. 24. Half of a former Carlsbad-twinned plagioclase crystal has been replaced by microcline (black and white; grid-twinned; left side) up to the nearly straight compositional plane that extends down through the photo. The plagioclase in the other half of the Carlsbad twin (white; right side) is in early stages of replacement by microcline (grid-twinned islands) in which the albite twinning of the grid-twinning is parallel to the albite twinning of the plagioclase. Outside the field of view, other plagioclase grains have rim myrmekite against the microcline. Desolation Valley granodiorite north of Aloha Lake and plotted on Loomis' geologic map. Thin section 247 from Loomis collection.