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The Isle of Purbeck, not a true island but a peninsula, is in the county of Dorset, England. It is bordered by the English Channel to the south and east, where steep cliffs fall to the sea; and by the marshy lands of the River Frome and Poole Harbour to the north. Its western boundary is less well defined, with some medieval sources placing it at Flower's Barrow above Worbarrow Bay.〔An inquisition taken at Corfe Castle in 1370 quotes a document that affirms "''that the whole Isle of Purbeck is a warren of our lord the King and pertains to his said castle, and it extends from a path which is between Flouresberi and the wood of Wytewey and thence as far as Luggerford, from that to the bridge of Wareham, and so along the sea, in an easterly direction, to a place called the Castle of Stodland; thence by the sea-coast to the chapel of St Aldhalm, and from thence still by the sea-coast towards the west until it again reaches the aforesaid place of Flouresberi''". Mentioned in 〕 The most southerly point is St Alban's Head (archaically St. Aldhelm's Head). It is suffering erosion problems along the coast. The whole of the Isle of Purbeck lies within the local government district of Purbeck, which is named after it. However the district extends significantly further north and west than the traditional boundary of the Isle of Purbeck along the River Frome. In terms of natural landscape areas, the southern part of the Isle of Purbeck and the coastal strip as far as Ringstead Bay in the west, have been designated as National Character Area 136 - South Purbeck by Natural England. To the north are the Dorset Heaths and to the west, the Weymouth Lowlands. ==Geology== The geology of the Isle is complex. It has a discordant coastline along the east and concordant coastline along the south. The northern part is Eocene clay (Barton Beds), including significant deposits of Purbeck Ball Clay. Where the land rises to the sea there are several parallel strata of Jurassic rocks, including Portland limestone and the Purbeck beds. The latter include Purbeck Marble, a particularly hard limestone that can be polished (though mineralogically, it is not marble). A ridge of Cretaceous chalk runs along the peninsula creating the Purbeck Hills, part of the Southern England Chalk Formation that includes Salisbury Plain, the Dorset Downs and the Isle of Wight. The cliffs here are some of the most spectacular in England, and of great geological interest, both for the rock types and variety of landforms, notably Lulworth Cove and Durdle Door, and the coast is part of the Jurassic Coast World Heritage Site because of the unique geology. In the past quarrying of limestone was particularly concentrated around the western side of Swanage, the villages of Worth Matravers and Langton Matravers, and the cliffs along the coast between Swanage and St. Aldhelm's Head. The "caves" at Tilly Whim are former quarries, and Dancing Ledge, Seacombe and Winspit are other cliff-edge quarries. Stone was removed from the cliff quarries either by sea, or using horse carts to transport large blocks to Swanage. Many of England's most famous cathedrals are adorned with Purbeck marble, and much of London was rebuilt in Portland and Purbeck stone after the Great Fire of London. By contrast, the principal ball clay workings were in the area between Corfe Castle and Wareham. Originally the clay was taken by pack horse to wharves on the River Frome and the south side of Poole Harbour. However, in the first half of the 19th century the pack horses were replaced by horse-drawn tramways. With the coming of the railway from Wareham to Swanage, most ball clay was dispatched by rail, often to the Potteries district of Staffordshire. Quarrying still takes place in Purbeck, with both Purbeck Ball Clay and limestones being transported from the area by road. There are now no functioning quarries of Purbeck Marble. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Isle of Purbeck」の詳細全文を読む スポンサード リンク
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