Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

bituminous
     adj : resembling or containing bitumen; "bituminous coal"