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Grandfather Falls is the highest waterfall on the Wisconsin River. The total drop is 89 feet,〔Smith, Leonard S. ''The Water Powers of Wisconsin, Wisconsin Geological and Natural History Survey, Bulletin No. XX'' (Madison: Published by the State, 1908), p. 144. Smith lists the drop as 89 1/2 feet.〕〔Wisconsin Public Service Corporation ''Grandfather Falls: A Pictorial Souvenir of a Major Public Service Hydro-Electric Improvement'' (publication date unknown, estimated 1939) gives the hydroelectric head as 94 feet, but this is partly due to backwater further up stream. The as of 2012-11-07 lists the head as varying between 92 and 93 feet.〕 spread out in a series of cascades over about one mile. The upper third of the falls and most of the flow, except in the spring, is diverted through a canal and a series of penstocks to feed hydroelectric generators. Grandfather Falls dam and power generating facility is owned and operated by Wisconsin Public Service Corporation. The cascade has been known historically as Grandfather Bull Falls 〔 〕 and as Boileaux Rapids. 〔 〕 Other phonetic variations on Boileaux such as Beauleaux 〔 〕 and Brearbeaux 〔 〕 are also sometimes seen in older accounts and maps. The Ojibwe name for the cascade was ''Konajewun'' which means "long falls." 〔 Calkins ''Op. cit.'', p. 121. 〕 Many of the falls and rapids on the Wisconsin River had the word "Bull" inserted in the name, such as Big Bull Falls at what is now Wausau and Jenny Bull Falls at what is now Merrill. These derive from ''voyageurs'' working for John Baptiste DuBay, who ran a trading post for the John Jacob Astor's American Fur Company near Fort Winnebago, and built a pioneering trading post and homestead near Knowlton. While traveling up stream, a party of these ''voyageurs'' encountered the rapids at Mosinee and named it ''Taureau'', French for "bull." When they encountered the rapids at Wausau, which were bigger, they named them ''Gros Taureau'' — "Big Bull." When they encountered the much larger rapids 40 miles further up stream, they named them ''Taureau Grand-père.'' This began a tradition for naming all the falls on the upper Wisconsin.〔Marchetti, Louise ''History of Marathon County, Wisconsin and Representative Citizens'' (1913), p. 65.〕 ==Geologic history== Several hundred million years ago, the northern highlands of Wisconsin were an alpine mountain range. Beneath this range, igneous rock formed which now is called pre-Cambrian bedrock, the top layers of the mountains having been worn down by erosion. In more recent geologic time, glaciers scoured the surface exposing this pre-Cambrian rock in many areas, leaving irregular drainage throughout the north woods with many rapids and falls as features of the streams.〔Martin, Lawrence ''The Physical Geography of Wisconsin'' (Madison: University of Wisconsin Press, 1916), p. 376. The text is available on line at http://www.archive.org/details/physicalgeograph00martrich.〕 Grandfather Falls lies in this pre-Cambrian rock bed,〔Smith, p. 144.〕 and is thus a remnant of the physical geography of this ancient mountain range. 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「Grandfather Falls」の詳細全文を読む スポンサード リンク
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