Musings in Durlston Bay

摘要

Peter Fookes writes Durlston Bay is at the eastern end of the Isle of Purbeck in the English county of Dorset, much of it being within Durlston Country Park. It is part of the East Devon and Dorset World Heritage Site, backed by fairly high cliffs with a small beach at their foot (Fig. 6), and has been much studied since Thomas Webster first described its geology in 1816. The cliffs contain small faults and landslips, and form the type section of the Purbeck Beds (top Jurassic and bottom Cretaceous). Aficionados will know that these beds are well-bedded shallow water limestones (good building stones, especially Purbeck 'marble'), shales and clays which are thought to have been deposited in shallow lake or lagoonal environments, with occasional marine intercalations in a climate which resembles that of the Mediterranean today. Beds strike east-west with a shallow northerly dip resulting from Tertiary Alpine movements. They are famous for a fairly abundant freshwater, and more rare marine, fauna particularly gastropods, bivalves.