Any of various kinds of stone of a dun or dull brown colour, esp. magnesian limestone or (occasionally) dolerite.

any sedimentary rock containing a high proportion of phosphates, often used as a fertilizer; phosphorite.

Originally: †a fine or smooth-grained sandstone (obsolete). In later use: a sedimentary rock composed of medium-sized particles (commonly defined as…

A sedimentary rock composed of glacial till compacted into hard rock.

Rock, or a rock formation, deposited by water flowing in a thin sheet.

A sedimentary rock which is similar in appearance to a tillite but is not known to be of glacial origin; a sedimentary rock composed of…

A sediment or rock deposited, or presumed to have been deposited, by a turbidity current.