molasse
/mə(ʊ)ˈlas/(also mollasse) Geology
noun
Originally (formerly also with capital initial): a deposit of soft greenish sandstone mixed with marls and fossiliferous conglomerates, of Miocene to Oligocene age, found along the northern edge of the Alps. Later also (more generally): any thick paralic sedimentary deposit formed after a period of orogeny and consisting of soft, ungraded sandstones, shales, marls, etc.
Origin
Late 18th century; earliest use found in Richard Kirwan (1733–1812), chemist and mineralogist. From French molasse, mollasse, use as noun of molasse, adjective, probably from classical Latin mollis + French -asse, augmentative suffix (from classical Latin -ācea, feminine of -āceus: see -aceous), with form altered after French (regional) mole, variant of meule millstone.