Argillaceous
/ɑːd͡ʒɪlˈeɪʃəs/
"Argillaceous" in a Sentence (2 examples)
[…] natural colossi from two to five hundred feet high, done in argillaceous sandstone or a singular species of conglomerate, all of which owe their existence almost entirely to the agency of wind.
The gleam of the land is in its rocks, the fine-grained argillaceous rocks, here, not purple or grey, but green of living stone.