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 the resultant length increases exponentially faster than the increase of scale of measurement, there is no such thing as "an approximate answer" to this question. This is referred to as the coastline paradox. A coastline is fractal-like — which means that it has self-similar properties, similar at every scale — therefore the closer the observer looks, the more detail is revealed, leading to a greater overall length. The United Kingdom's coastline is more broken than coastlines of many other countries. It has a fractal or Hausdorff dimension or 'wiggliness' of 1.25, which is comparatively high; the Australian coastline for example