argillaceous
/ˌɑːdʒɪˈleɪʃəs
/adjective Geology
(Of rocks or sediment) consisting of or containing clay.It is predominantly found in the marl areas but also, more rarely, in fine-grained argillaceous limestones....
- The 284 m section is composed of calcareous shales, argillaceous limestone, and limestone.
- They were found as scattered individuals in the argillaceous limestones.
Origin
Late 17th century: from Latin argillaceus (from argilla 'clay') + -ous.