The Purbeck Group (or Purbeck Beds) 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. The Purbeck Group is famous for its fossils of reptiles and early mammals. Rocks of this age have in the past been called the Purbeckian stage by European geologists. The Purbeckian corresponds with the Tithonian and Berriasian stages of the internationally used geologic timescale.