Russia, Subpolar Ural, Kozhim river valley. White, light gray marbled limestones. Include microlayers of quartz-mica composition, the content of quartz grains in them sometimes reaches 30–35%. Under the microscope of the rock, a granoblastic structure with relics of an uneven-grained - blastopsammite and blastoaleurite is found; layered, banded texture and consist of a calcite heterogeneous aggregate (70–99%) with intercalations of quartz grains (up to 25%) and microlayers of carbonaceous-chlorite-sericite, muscovite-chlorite composition.
