Examples from the Web for argillaceous
Its powder is a light red, and emits an argillaceous odor when wetted.
The solid surface of the earth is mainly composed of gravel, of calcareous, and argillaceous strata.
Among the fluviatile deposits, argillaceous marl beds now play an important part.Old Rome|Robert Burn
Here is the same induration of sandstone by means of fusion, that in the argillaceous strata has produced jasper.Theory of the Earth, Volume 1 (of 4)|James Hutton
It is not volcanic, but consists of argillaceous schist and quartzite.