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
Operational Guidelines for the Implementation of the World Heritage Convention the World Heritage List and the way to it is to be found in Chapter 2. Before properties can be proposed for inscription as a World Heritage Site, they must be on the tentative lists of the States Parties. The properties must be of Outstanding Universal Value (OUV) which means "cultural and/or natural significance which is so exceptional as to transcend national boundaries and to be of common importance for present and future generations of all humanity". There are ten criteria for the assessment of OUV. Criteria (i)-(vi) for cultural heritage, (vii)-(x) for natural heritage. Properties nominated under criteria (i)