A series of rocks, the oldest or lowest part of the Jurassic System, noted for its fossils.
Origin of lias
Originally dialectal, from Old French liois (“compact limestone") (French liais).
Lias Sentence Examples
The Permian may be represented, but the Trias is absent, and in general the older Palaeozoic rocks are overlaid directly by the Rhaetic and Lias.
It is, however, not impossible that the metamorphic series includes also some of the Lias.
Another well-known bed, formerly known as the "Bristol" or "Lias" Bone Bed, exists in the form of several thin layers of micaceous sandstone, with the remains of fish and saurians, which occur in the Rhaetic Black Paper Shales that lie above the Keuper marls in the south-west of England.
To the Lias also can be traced back the Neuroptera, the Trichoptera, the orthorrhaphous Diptera and, according to the determination of certain obscure fossils, also the Hymenoptera (ants).