ETYM as. scealy, scalu. Related to Scalme, Shell.
A sedimentary rock formed by the deposition of successive layers of clay.
Laminated rock of consolidated clay or mud.
Fine-grained and finely layered sedimentary rock composed of silt and clay. It is a weak rock, splitting easily along bedding planes to form thin, even slabs (by contrast, mudstone splits into irregular flakes). Oil shale contains kerogen, a solid bituminous material that yields petroleum when heated. + prikaži više