Source : Webster's Revised Unabridged Dictionary (1913)

Shale \Shale\, n. [AS. scealy, scalu. See {Scalme}, and cf.
   {Shell}.]
   1. A shell or husk; a cod or pod. ``The green shales of a
      bean.'' --Chapman.

   2. [G. shale.] (Geol.) A fine-grained sedimentary rock of a
      thin, laminated, and often friable, structure.

   {Bituminous shale}. See under {Bituminous}.

Bituminous \Bi*tu"mi*nous\, a. [L. bituminosus: cf. F.
   bitumineux.]
   Having the qualities of bitumen; compounded with bitumen;
   containing bitumen.

         Near that bituminous lake where Sodom flamed. --Milton.

   {Bituminous coal}, a kind of coal which yields, when heated,
      a considerable amount of volatile bituminous matter. It
      burns with a yellow smoky flame.

   {Bituminous limestone}, a mineral of a brown or black color,
      emitting an unpleasant smell when rubbed. That of Dalmatia
      is so charged with bitumen that it may be cut like soap.
      

   {Bituminous shale}, an argillaceous shale impregnated with
      bitumen, often accompanying coal.