Geography of Dorset is the Blackmore Vale, a relatively low-lying area of clays and limestones of Jurassic age. The south-east of the county forms part of the Hampshire Basin, an asymmetric syncline covered in sands and gravels of Paleogene age. The main rivers in the county are the Stour, Frome and Piddle. The Stour is the county's largest river, although its source is in the neighbouring county of Wiltshire. The Frome and Piddle both lie wholly within the county. The whole of Dorset's coastline is designated part of the Jurassic Coast World Heritage Site, and contains examples of many different coastal landforms, reflecting
Coastline of the United Kingdom island groups in the UK are as follows: The Channel Islands (including Jersey, Guernsey, Alderney and Sark) and the Isle of Man are not part of the UK; they are self-governing Crown dependencies therefore their coastlines are not coastlines of the United Kingdom. Peninsulas around the UK coast include: Bays, sea lochs (loughs) and large estuaries include: Coastline of the United Kingdom The coastline of the United Kingdom is formed by a variety of natural features including islands, bays, headlands and peninsulas. It consists of the coastline of the island of Great Britain and the north-east coast of the island