The chief physical feature of Devonshire, a feature without parallel in any other part of England, is the Forest of Dartmoor, the great upland, some twenty miles long and eighteen miles broad, which occupies so large a part of the southern half of the county. It is all granite, the largest mass of granite in England, and forms part of a chain of outcrops of that formation extending from Devonshire to the Scilly Isles. The word "forest," it should be remembered, originally meant, not a wood, but a hunting-ground. No part of the open moor is now covered with trees, nor is it likely, considering the poorness of the soil, that it ever was so covered, although roots and other remains of trees have been found in various parts of it. In early days it was a royal hunting-ground, and most of it is still Crown property, forming part of the Duchy of Cornwall. The most prominent feature of the moor, which contains the highest ground in England south of Ingleborough in Yorkshire, are the isolated rocky heights called tors, some 170 in number, many of which have been weathered, not only into very rugged and highly picturesque, but even into most strange and fantastic shapes; in many cases having their steep slopes strewn with fallen fragments of rock, some of them tons in weight, forming what are known on the moor as "clitters" or "clatters." The highest points are High Willhays, 2039 feet; Yes Tor, 2029 feet, only half a mile away from its rival, Newlake, 1983 feet; Cuthill, 1980 feet; and Great Lynx Tor, 1908 feet above sea-level; and among the most striking and picturesque are Great Lynx Tor, Staple Tor, Mis Tor, and Vixen Tor, although many others are remarkable for their strange and time-worn outlines. The moor is seamed by many valleys and ravines, not a few of which are, in parts, well-wooded, each with its swiftly-flowing stream or river, and many of them most picturesque and beautiful. Such, in particular, are the Valley of the Dart, especially including Holne Chase and above; of the Teign near Fingle Bridge; of the Tavy at Tavy Cleave; of the Lyd at Lydford, and of the Plym at the Dewerstone. [Illustration: Tavy Cleave, showing disintegrated granite] Dartmoor is distinguished in being the coldest and rainiest part of Devonshire, and to these two features of its climate are no doubt largely due the fogs which so frequently envelope it. Its great extent and its heavy rainfall make the moor the main watershed of the county. Most of its rivers have their sources in the bogs, which are a well-known and somewhat dangerous feature of the district, and of which the most remarkable are Fox Tor Mire, Cranmere Bog, and Cuthill Bog.