Figure F49. Photomicrograph of volcaniclastic sediment (Unit 14), illustrating very fine grained silica-clay altered volcanic fragments (dark) rimmed by fine crystalline quartz (interval 193-1188A-14R-1, 105-106 cm, in cross-polarized light; width of view = 2.75 mm. Photomicrograph ID# 1188A_63 [modified]; thin section 14).