Answer:
Mature, Shale
Explanation:
shale is a general term for all kinds of clay rich sedimentary rocks. Shales are the most abundant kind of all sedimentary rocks accounting for around 60% of the stratigraphic column. .Shales are fine-grained sedimentary rocks with a clay content in excess of ∼40% and clay-sized particles along with clay minerals comprising 25% of total rock volume.