Fig. 23. Perthitic Carlsbad-twinned K-feldspar (black and dark gray) enclosing cataclastic fragments of plagioclase (light gray) some of which are myrmekitic. The K-feldspar also penetrates the plagioclase along microfractures (right side). Pyramid Peak granite at Rockbound Pass, north end of pluton. Thin section 275 from Loomis collection.