Purbeck Group
The Purbeck Group is an Upper Jurassic to Lower Cretaceous lithostratigraphic group (a sequence of rock strata) in south-east England. The name is derived from the district known as the Isle of Purbeck in Dorset where the strata are exposed in the cliffs west of Swanage.
| Purbeck Group | |
|---|---|
| Stratigraphic range: | |
Strata of the Purbeck Group in Durlston Bay, Dorset | |
| Type | Group |
| Sub-units | Lulworth Formation, Durlston Formation and Haddenham Formation |
| Underlies | Wealden Group |
| Overlies | Portland Group |
| Thickness | 45 to 120 m in South Dorset, 77 to 186 m in the Weald |
| Lithology | |
| Primary | Mudstone, Limestone |
| Other | evaporites, chert |
| Location | |
| Region | Europe |
| Country | UK |
| Extent | Southern England |
| Type section | |
| Named for | Isle of Purbeck |
| Location | Durlston Bay cliffs |
The Purbeck Group is famous for its fossils of reptiles and early mammals. This sequence of rocks has gone by various names in the past including amongst others the Purbeck Beds, Purbeck Formation, Purbeck Limestone Formation and Purbeck Stone.
Rocks of this age have in the past been called the Purbeckian stage by European geologists. The Purbeckian corresponds with the Tithonian to Berriasian stages of the internationally used geologic timescale.
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