DARTMOOR  , a high

plateau in the south-west of Devonshire, England . Its length is about 23 M. from N. to S. and its extreme breadth 20 m., the mean altitude being about 15oo ft . The area exceeding l000 ft. in elevation is about 200 sq. m . It is the highest and easternmost in a broken chain of granitic elevations which extends through Cornwall to the Scilly Isles . The higher parts are open, bleak and wild, strongly contrasting with the more gentle scenery of the well-wooded lowlands surrounding it . Sloping heights rise from the main tableland in all directions, crested with broken masses of granite, locally named tors, and often singularly fantastic in outline . The highest of these are Yes Tor and High Willhays in the north-west, reaching altitudes of 2028 and 2039 ft . Large parts of the moor, especially in the centre, are covered with morasses ; and head-waters of all the principal streams of Devonshire (q.v.) are found here . Two main roads cross the moor, one between Exeter and Plymouth, and the other between Ashburton and Tavistock, intersecting at Two Bridges . Both avoid the higher part of the moor, which, for the rest, is traversed only in part by a few rough tracks . The central part of Dartmoor was a royal forest from a date unknown, but apparently anterior to the Conquest . Its woods were formerly more extensive than now, but a few small tracts in which dwarf oaks are characteristic remain in the lower parts .

Previous to 1337, the forest had been granted to

Richard, earl of Cornwall, by Henry III., and from that time onward it has belonged to the duchy of Cornwall . The districts immediately surrounding the moor are called the Venville or Fenfield districts . The origin of this name is not clear . The holders of land by Venville tenure under the duchy have rights of pasture, fishing, &c. in the forest, and their main duty is to " drive " the moor at certain times in order to ascertain what head of cattle are pastured thereon, and to prevent trespassing . The antiquarian remains of Dart-moor are considered among those of Devonshire . Dartmoor convict prison, near Princetown, was adapted to its present purpose in 185o ; but the original buildings were erected in 18o9 for the accommodation of French prisoners . A tract of moorland adjacent to the prison has been brought under cultivation by the inmates . See S . Rowe, Perambulation of the . . . forest of Dartmoor (Plymouth, 1848) ; J . L . W .

Page, Exploration of Dartmoor (London, 1889) ; S . Baring-Gould, Book of Dartmoor (London, 1900) .