Source : Webster's Revised Unabridged Dictionary (1913)

Calcareous \Cal*ca"re*ous\, a. [L. calcarius pertaining to lime.
   See {Calx}.]
   Partaking of the nature of calcite or calcium carbonate;
   consisting of, or containing, calcium carbonate or carbonate
   of lime.

   {Calcareous spar}. See as {Calcite}.

Source : WordNet®

calcareous
     adj : composed of or containing or resembling calcium carbonate or
           calcite or chalk [syn: {chalky}]