Haldon Hills
Coordinates: 50°38′N 3°33′W / 50.64°N 3.55°W The Haldon Hills, usually known simply as Haldon, is a ridge of high ground in Devon, England. It is situated between the River Exe and the River Teign and runs northwards from Teignmouth, on the coast, for about 24 km (15 mi) until it dwindles away north west of Exeter at the River Yeo, just south of Crediton. The highest points of just over 250 metres (820 ft) lie to the south west of Exeter. The southernmost part is known as Little Haldon; it is partially separated from the main bulk of the hills by a col formed by the valleys of the Dawlish Water to the east and the valley at Rixdale to the west.
Haldon is composed of New Red Sandstone covered by a more resistant layer of Upper Greensand. On the highest ground is a layer of gravel containing many flints that is up to 18 metres (60 ft) deep; it is all that remains of a cover of chalk some 180 metres (600 ft) thick that was deposited during the Late Cretaceous and then dissolved away during the tropical climate in the Eocene.
Around the highest ground there are several other rock types. To the south west, around Chudleigh, are limestones of Devonian age, but further north there are shales, sandstones and cherts from the Carboniferous. These are cut through in places by igneous intrusions, mainly of dolerite (quarried at Trusham), and there was also a degree of mineralisation which led to the development of a number of mines around the valley of the River Teign; ores of lead, iron, copper, manganese and barite were mined here, for instance at Wheal Exmouth.
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