Theory of the Earth that used the biblical account of the Noachian Deluge to explain major geologic phenomena. Before about 1800 the biblical flood was frequently cited as the cause of fossilization, sedimentation, deposits, stratifications, etc. In the 19th century the theory was extended by Cuvier, Buckland, and others, who believed in a series of deluges, which had caused the extinction of species and the breaks between major formations. The term is also sometimes (incorrectly) used to describe Werner’s theories.