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]

Source: The Collaborative International Dictionary of English v.0.48
 

argillaceous adj : resembling or containing clay; "argillaceous rocks" [syn: clayey] [ant: arenaceous]

Source: WordNet (r) 2.0
 

Argillaceous \Ar`gil*la"ceous\, a. [L. argillaceus, fr. argilla.]

Of the nature of clay; consisting of, or containing, argil or clay; clayey.

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

Argillaceous iron ore, the clay ironstone.

Argillaceous schist or state. See Argillite.

Source: Webster's Revised Unabridged Dictionary (1913)