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}} Sugar Loaf is a bluff on the Mississippi River topped by a rock pinnacle, overlooking the city of Winona, Minnesota, United States. The name "Sugar Loaf" is sometimes taken to mean just the rock pinnacle, which was created by quarrying in the 19th century. The bluff stands above the junction of U.S. Route 61 and State Highway 43. It towers over Lake Winona (a former part of the Mississippi River's main channel), and the pinnacle rises more than above the remainder of the bluff. Sugar Loaf was listed on the National Register of Historic Places in 1990 for having local significance in the theme of entertainment/recreation. It was nominated for being one of Minnesota's most famous landmarks to early travelers and tourists; a popular subject for stereopticon images, travel literature, and folklore.〔 ==Rock pinnacle== Sugar Loaf's distinctive pinnacle resulted from quarrying the bluff's limestone cap layer through most of the 1880s, which was then used for Winona’s sidewalks and stone buildings. The mining was done by two brothers, John and Stephen O'Dea. The use of limestone (Oneota dolomite—a sedimentary limestone composed mainly of calcium carbonate and magnesium) began with the need to improve city sidewalks, most of which were made of wood and burned in the 1862 fire that destroyed 90 percent of the downtown district. Many miles of this limestone were installed before the turn of the 20th century and met with such success that a city ordinance was passed in late 1890 specifying stone-only for sidewalks. Buildings in the area also began to utilize the stone because of its texture. Quarry operations were shut down in 1887. A rare event occurred in March 2004. Tons of limestone sheared off the northwest face of the pinnacle, leaving a dark trail of rock rubble in the snow, down a lower cliff face, and onto the tree-covered slope below. The cascade stopped about short of the nearest house. The layers of stone came loose and fell because of the freezing and thawing action of water over time, especially from the unusually wet winter. 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「Sugar Loaf (Winona, Minnesota)」の詳細全文を読む スポンサード リンク
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