Stratus (St) Found at very low levels (less than 2000 meters, or 6500 feet), stratus clouds are thick, large, heavy-looking gray clouds that dominate the sky. Precipitation normally does not occur with this cloud, although drizzle or mist may be observed.
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles. Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism.
Each kind of sedimentary rock turns into a different kind of metamorphic rock-limestone turns into travertine or marble, and shale turns into slate, and sandstone turns into quartzite.Even though slate is a metamorphic rock, it still looks a lot like a sedimentary rock-it is still in thin layers. A raw (uncut) diamond.hen sedimentary rocks like limestone or shale were under water, sometimes the weight of the water pressed them so hard that they actually changed the way their molecules locked together and became a different kind of rock. Metamorphosis means changes form, and that's why we call these metamorphic rocks.