Fig. 18. Orthoclase megacryst (light gray) partly inverted to microcline, showing corner of the megacryst where the adjacent cataclastically broken groundmass minerals sweep around the top edge of the megacryst and split and sweep around the right edge of the megacryst. Larger biotite crystals (brown) are entrained parallel to the shear direction and form the upper boundary of the orthoclase. Below these biotite crystals is a train of tiny crystals that are remnants of a former shear plane that parallels these biotite crystals. This train is nearly continuous, but the orthoclase is not off-set by the shearing. The orthoclase extends into and has replaced minerals in the shear plane in the upper right corner of the megacryst. A myrmekitic inclusion occurs in the lower left (above the scale), but the quartz vermicules are not visible in this orientation. Quartz (white, gray, black) occurs on right edge of the megacryst.