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A conical hill (also cone or conical mountain) is a landform with a distinctly conical shape. It is usually isolated or rises above other surrounding foothills, and is often, but not always, of volcanic origin. Conical hills or mountains occur in different shapes and are not necessarily geometrically-shaped cones; some are more tower-shaped or have an asymmetric curve on one side. Typically, however, they have a circular base and smooth sides with a gradient of up to 30°. Such conical mountains are found in all volcanically-formed areas of the world such as the Bohemian Central Uplands in the Czech Republic, the Rhön in Germany or the Massif Central in France. == Term == The conical hill as a geomorphological term first appeared in the German language, as ''Kegelberg'', coined by Goethe and geologists of his era. From their natural appearance these were mostly basaltic or phonolitic landforms in the shape of a mathematical cone, hence why the term came to be used in the early geological literature. The first systematic geological mapping of the Kingdom of Saxony, proposed and started by Abraham Gottlob Werner, describes, in his later works, numerous mountains and hills of volcanic or subvolcanic origin as ''Kegel'' ("cone") or ''Kegelberg'' ("conical hill/mountain"). The term was introduced more definitively by Carl Friedrich Naumann in ''Notes to Section VII of the Geognostic Charter of the Kingdom of Saxony and its Adjacent Territories'' (''Erläuterungen zu Section VII der geognostischen Charte des Königreiches Sachsen und der angränzenden Länderabtheilungen'') thus: ''"The ordinary form of basalt and phonolitic hills is generally so wonderfully uniform that you can often recognize them even from a distance. They are cones. Of course, this typical form has many variations; the () round base may be elongated, the peak may take the form of a rocky crest or ridge, ... but most forms can be reduced at least to a conical or a cone-segment shape. ... Flat ridges are then arranged in rows, out of which rise only a very isolated basalt or phonolite cones."''〔Naumann: Section VII, pp. 61-62〕 In this work, which was published by Naumann and later revised by Bernhard Cotta, the most important hills are described in the relevant map sheets, for example: ''33. The Mittenberg, a conical hill in the centre between Tollenstein, Schönfeld and Neuhütte; rock, coarse splinters, with grey feldspar crystals.''〔Naumann: Section VII, p. 94〕 Today the descriptors "cone", "conical hill" or "conical mountain" are mainly used as morphological terms in geography for a steep-sided, isolated hill or mountain, because they are not always seen or described in connexion with volcanic processes.〔Hartmut Leser (ed.): Diercke Wörterbuch Allgemeine Geographie. Munich, (dtv) 2005, p. 421 ISBN 3-423-03422-X.〕 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「conical hill」の詳細全文を読む スポンサード リンク
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