Obs. Also 8 werk. [Of obscure origin.] (See quots.)
1707. Sloane, Jamaica, I. Pref. B 2 b. I know not but that the several Species of new Ferns … may be discover’d upon some of the Stones or Slates called Werk, which lie in plenty in the Strata over the Cole-pits in many Places of England.
1759. B. Martin, Nat. Hist., I. 68. In several of the Coal Pits of this Country [Somerset], the Veins are covered with a Shell of hard, and stony Substance called Wark, which splits like Slate, but is much more brittle.
