argillaceous

from WordNet (r) 3.0 (2006)

argillaceous
    adj 1: resembling or containing clay; "argillaceous rocks" [syn:
           {argillaceous}, {clayey}] [ant: {arenaceous}, {sandlike},
           {sandy}]

from The Collaborative International Dictionary of English v.0.48

Argillaceous \Ar`gil*la"ceous\, a. [L. argillaceus, fr.
   argilla.]
   Of the nature of clay; consisting of, or containing, argil or
   clay; clayey.
   [1913 Webster]

   {Argillaceous sandstone} (Geol.), a sandstone containing much
      clay.

   {Argillaceous iron ore}, the clay ironstone.

   {Argillaceous schist} or {state}. See {Argillite}.
      [1913 Webster]