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Clough Head () (meaning: ''hill-top above the ravine'') is a fell, or hill, in the English Lake District. It marks the northern end of the main ridge of the Helvellyn range and is often walked as part of the ridge walk. The fell stands south of the village of Threlkeld and the A66 road, and it forms the steep eastern side of the tranquil valley of St John's in the Vale. On its western side the fell displays a dark mass of rocky crags and a deep-set rocky ravine. On the other side it has smooth grassy slopes. Beneath the north face is the steep valley or clough from which Clough Head gets its name. Also beneath the steep northern face lies the lower hill of Threlkeld Knotts, a granite hill which has been much quarried round its margin. A number of different types of rock are found on and around Clough Head, which were formed in very different circumstances. These include deep-sea sedimentation, effusive volcanic lava flows, explosive volcanism, an intrusion of granite, mineralisation and finally glacial sculpting. To understand the geology of Clough Head is to understand much of the geology of the Lake District. An old route known as the Old Coach Road passes beneath Clough Head. Most of the fell is Open Access land, which walkers can enter from either end of the Old Coach Road, or from a lane south of the village of Threlkeld. Four main routes lead to the summit. ==Topography== With a height of 726 m, Clough Head is the lowest summit of the Helvellyn range. Gentle grass-covered slopes on the south and east sides of the fell drop to a broad col and to Mosedale, both of which separate Clough Head from Great Dodd, its neighbour to the south. To the north of the summit the ground drops abruptly down a steep scree-covered and craggy slope which marks the northern end of the Helvellyn range. This face is called Red Screes from the colour of the rock. Beneath Red Screes is the lower, rounded, grassy hill of Threlkeld Knotts. This hill rises gently from the valley of the River Glenderamackin, which separates the Helvellyn range of fells from Blencathra and the northern Lakeland fells. A steep valley to the east of Threlkeld Knotts, which begins immediately below Red Screes, is the clough from which Clough Head is named. In the bottom of this valley there is a sheepfold known as Clough Fold.〔Ordnance Survey 1:25,000 Explorer map〕 Steep rocky crags guard the whole western side of the fell, rising abruptly from the green valley of St John's in the Vale. This western face of Clough Head, is steep, rough and rocky. The principal rock features are, from north to south: Buck Castle, Wanthwaite Crags and Bram Crag. South of Wanthwaite Crags is the very steep Fisher's Wife's Rake, a grassy break in the cliffs (though with scree) which allows determined fell-walkers to ascend the fell on this side. North of Bram Crag is a deep-seated rocky ravine called Sandbed Gill. This gill contains a considerable flow of water in its rocky gorge, but it often has only a dry bed by the time it gets down to valley level. North-east of the summit of Clough Head is the lesser top of White Pike. From here the ridge descends and gradually broadens into the rough expanse of Thelkeld Common. The western slopes of Clough Head drain into St John's Beck, which flows north into the River Greta, and which in turn joins the River Derwent at Keswick. The southern and eastern slopes drain into Mosedale and Mosedale Beck, which also joins the River Greta, via the River Glenderamackin.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Clough Head」の詳細全文を読む スポンサード リンク
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