Former name for what is now called the Early Jurassic epoch, dated at 199.6–175.6 Ma ago (Int. Commission on Stratigraphy, 2004), and comprises the Hettangian, Sinemurian, Lotharingian, Pliensbachian, and Toarcian stages. Blue-grey shales and muddy limestones are typical of the Lias, with Dactylioceras and Gryphaea among the more important fossils found in the extensive outcrops of England and France.