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Helvellyn () (possible meaning: ''pale yellow moorland'') is a mountain in the English Lake District, the highest point of the Helvellyn range, a north-south line of mountains to the north of Ambleside, between the lakes of Thirlmere and Ullswater. Helvellyn is the third-highest point both in England and in the Lake District, and access to Helvellyn is easier than to the two higher peaks of Scafell Pike and Sca Fell. The scenery includes three deep glacial coves and two sharp-topped ridges on the eastern side (Striding Edge and Swirral Edge). The volcanic rocks of which the mountain is made were formed in the caldera of an ancient volcano, many of them in violently explosive eruptions, about 450 million years ago during the Ordovician period. During the last ice age these rocks were carved by glaciers to create the landforms seen today. Since the end of the last ice age, small populations of arctic-alpine plants have survived in favourable spots on rock ledges high in the eastern coves. Rare to Britain species of alpine butterfly, the Mountain Ringlet, also live on and around Helvellyn. Mineral veins, some with deposits of the lead ore galena, do exist within Helvellyn’s rocks, but attempts to find sufficient quantities of lead to be worth mining have not been successful. Tourism has been a more successful industry in the area. For over two hundred years visitors have been drawn by the lake and mountain scenery of the Lake District, and many have made their way to the top of Helvellyn. Among the early visitors to Helvellyn were the poets Samuel Taylor Coleridge and William Wordsworth, both of whom lived nearby at one period. Many routes up the mountain are possible so that it may be approached from all directions. The view from the top is one of the most extensive over the Lake District, and on a clear day the view can also stretch from Scotland to Wales. However, traversing the mountain is not without dangers; over the last two hundred years there have been a number of fatalities. The artist Charles Gough is more famous for his death on Striding Edge in 1805 than for what he achieved in his life. Among many human feats upon the mountain, one of the strangest was the landing and take-off of a small aeroplane on the summit in 1926. ==Topography== The top of Helvellyn is a broad plateau, trending roughly from north-west to south-east for about a kilometre between Lower Man and the start of Striding Edge. Throughout this distance it remains more than 900 m high. To the west the ground drops gently at first but then more steeply down to Thirlmere, while on the eastern side three deep glacial coves, each backed by high cliffs, are separated by two spectacular sharp ridges or arêtes. The middle of these coves contains Red Tarn. Like much of the main ridge of the range, Helvellyn stands on the watershed between Thirlmere and the Derwent river system to the west, and Ullswater and the Eden river system to the east.〔Ordnance Survey 1:25,000 Explorer map〕 Streams on the west side drain directly into Thirlmere, apart from Helvellyn Gill which flows into a parallel valley to the east of Great How and empties into St John's Beck. However, when Thirlmere reservoir was built, a leat was constructed to capture the water of Helvellyn Gill, so that it is now directed into the reservoir. A never-failing spring called Brownrigg Well exists 90 m below the summit of Helvellyn (about 500 m due west of the highest point) at the head of Whelpside Gill.〔 In the nineteenth century a leat was constructed to direct the water of this spring into the gill to its north to serve the needs of the Helvellyn Mine further down. This leat has now fallen into disuse. The gill it led to is not named on any map,〔No map, not even the Ordnance Survey 1:10,000 scale map, gives a name to this gill〕 but some authors have referred to it as Mines Gill. Whelp Side, between Whelpside Gill and Mines Gill, appears as a distinct shoulder of the mountain when seen from the west, largely grassy though with a few crags and boulders in places, and with coniferous plantations on its lower slopes which were planted to stabilise the land around the reservoir. North of Mines Gill are the Helvellyn Screes, a more craggy stretch of hillside, beneath the north-west ridge, with a loose scree covering in places. The deep coves on the rocky eastern side of Helvellyn drain into Ullswater. Water from Brown Cove and Red Tarn unite below Catstye Cam to form Glenridding Beck, which flows through Glenridding village to the lake, while Nethermost Cove drains into the same lake via Grisedale Beck and Patterdale village. Red Tarn, enclosed between Striding Edge and Swirral Edge, is about 25 m deep, but in the mid-nineteenth century a dam was built to increase its capacity and supply the needs of the Greenside Mine near Glenridding. That dam has now gone and the tarn has returned to its natural size. It contains brown trout and schelly, a species of whitefish found in only four bodies of water in the Lake District. A second reservoir was built around 1860 in Brown Cove, between Swirral Edge and Lower Man, along with one further down the valley in Keppel Cove. These provided water to generate hydroelectric power for the lead mine. The dam in Keppel Cove is still in place, but water now leaks through its base. The remains of the dam in Brown Cove can be seen, but again water leaks freely through it. It is unclear whether there ever was a natural tarn in Brown Cove. Guidebook writers before 1860 refer only to Keppel Cove Tarn to the north of Swirral Edge.〔 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「Helvellyn」の詳細全文を読む スポンサード リンク
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