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Calcareous Sandstone

lllustrated in 119 and 120 is a sandstone which would be classified as a quartz arenite sińce nearly all the grains are quartz. However, the rock contains substan-tial calcite both in Lhc form of shell fragments and as a cement bclween the quartz grains. The calcite can be distinguished by its higher relief - it appears grey in plane-polarized light (119) and by its high-order inlerference colours - mostly pale pinks and greens, seen with crossed polars (120). This sediment may bcst be described as a calcareous sandstone.

Calcareous Sandstone

119 Calcareous sandstone in plane-polarized light. Locality: Middle Jurassic, Isle of Skye, Scotland (x 13).

120 Calcareous sandstone with crossed polars. Locality: Middle Jurassic, Isle of Skye, Scotland (x 13).

127