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
Pre-Dorset number of occupations in the High Arctic as well, namely to the north of Baffin Island, on the islands of Devon and Ellesmere. One important site, Port Refuge, on Devon island, hosts occupations ascribed to the Pre-Dorset and others ascribed to Independence I. At this site, Pre-Dorset dwellings are clustered and show no mid-passage feature, whereas the Independence I dwellings are arranged linearly with mid-passage features. The Pre-Dorset is generally restricted to the Low Arctic, and given that incursions to the High Arctic are rare, incursions into Greenland from the High Arctic are even rarer. Grønnow and Jensen (2003:42-43) ascribe