Figure F7. A. Photomicrograph in plane-polarized light of Sample 187-1157A-2R-1, 30-33 cm (see "Site 1157 Thin Sections"), showing calcarenite sediment, which occurs adhering to a basalt breccia clast (not shown). Note the round to elongate shapes of the crystals and the presence of small to medium-sized Mn oxide concretions throughout. B. Photomicrograph of the same sample in reflected light showing round to elongate shapes of calcite crystals (bright areas) surrounded by interstitial clay (darker areas).