Figure F8. Digital photomicrograph (plane-polarized light) of a moderately sorted, fine-grained volcaniclastic sandstone with a silty clay matrix. Composed of angular detrital grains of biotite, hornblende, feldspar, and quartz. Rare subrounded plagioclase-phyric basalt grains and planktonic foraminifers (Sample 180-1118A-24R-5, 105-107 cm).