Min. [f. as prec. + -ITE.] Argillaceous schist, clay slate. Argillitic a., of or containing argillite. Craig, 1847.
1795. Mills, in Phil. Trans., LXXXVI. 39. Bare rocks … a variety of argillite.
1850. Dana, Geol., xiii. 564. The rock somewhat resembles an argillite.
