矽質粘土岩,粘板岩
Argillite \Ar"gil*lite\, n. [Gr. ? clay + -lite.] (Min.)
Argillaceous schist or slate; clay slate. Its colors is
bluish or blackish gray, sometimes greenish gray, brownish
red, etc. -- {Ar`gil*lit"ic}, a.
argillite
n : a sedimentary rock differing from shale in being bound by
silica and from slate in having no slate cleavages