a. [f. L. argillāceus + -OUS: see -ACEOUS.] Of the nature of clay; largely composed of clay; clayey.
1731. in Bailey.
1781. Dillon, Trav. Spain, 253. A mixture of argillaceous, or calcareous earth.
1794. Sullivan, View Nat., I. 486. The argillaceous hills of Tuscany.
1841. Trimmer, Pract. Geol., 88. The argillaceous odour given out by minerals containing alumina.
