Subdivisions
In southern England, the Lias Group is often divided into Lower, Middle and Upper subgroups. In Somerset the Lias is divided into the following formations (from top to base):
- Helwell Marl
- Doniford Shale
- Quantock Beds
- Kilve Shale
- Blue Lias
- St. Audries Shale
- Aldergrove Beds
It is underlain by the Late Triassic Penarth Group, and overlain, after a stratigraphic hiatus, by the Early Cretaceous Upper Greensand Formation.
In Dutch lithostratigraphy, the name Lias has no official status, however, it is often used for the lower part of the Altena Group in the subsurface of the Netherlands and the southern North Sea.
In northern Germany, the Lias Group consists of nine formations (from top to base):
- Opalinuston
- Dörnten-Formation
- Posidonia Shale
- Amaltheenton
- Capricornu-Formation
- Raricostaten-Formation
- Arieten Sandstone
- Liassicus Sandstone
- Psilonoten Sandstone
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