|
Cribarth is a hill in the Brecon Beacons National Park (Parc Cenedlaethol Bannau Brycheiniog) in Powys, southern Wales. The summit lies on the broken ridge at an elevation of 428m at OS grid reference SN 831143. To its west is a 426m high rounded top at SN 829144 which lies just to the northwest of a mile long ridge which forms the main bulk of the hill.〔Ordnance Survey Landplan mapping〕 The ridge attains a height of 423m high at its southwest end and this spot is marked by a trig point.〔Ordnance Survey Explorer map OL12 'Brecon Beacons National Park: western area'〕 Both of these latter high points are adorned by Bronze Age burial cairns.〔RCAHM(W) 1997. An Inventory of the Ancient Monuments in Breconshire (Brycheiniog): The Prehistoric and Roman Monuments (Part II). London. HMSO.〕 ==Geology== The hill is formed from both Carboniferous Limestone rocks and the Namurian age Twrch Sandstone (former 'Basal Grit') of the Marros Group (former 'Millstone Grit Series'), also dating from the Carboniferous Period. It lies on the northeast-southwest aligned geological structure known as the Cribarth Disturbance and indeed gives its name to that regionally important structure. The Disturbance is characterised locally by a tight anticline which follows the alignment of the summit ridge and which is accompanied by one or two lesser folds on its northwestern side. Numerous crags, restricted areas of broken limestone pavement and shakeholes adorn the slopes of this hill as do various man-made features relating to its geology and described below. The hill has been used by generations of geology students for mapping practice.〔British Geological Survey 1:50,000 map sheet 231 'Merthyr Tydfil' & accompanying memoir〕 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「Cribarth」の詳細全文を読む スポンサード リンク
|