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The Boring Lava Field is an extinct Plio-Pleistocene volcanic field zone with at least 32 cinder cones and small shield volcanoes lying within a radius of 13 miles (21 km) of Kelly Butte, which is approximately 4 miles (6 km) east of downtown Portland, Oregon, in the United States. The name is derived from the town of Boring, Oregon, which lies just to the southeast of the most dense cluster of lava vents. The zone became active at least 2.7 million years ago, and has been extinct for about 300,000 years.〔 The Portland metropolitan area, including suburbs, is one of the few places in the continental United States to have extinct volcanoes within a city's limits; Bend, Oregon is another; for example Pilot Butte is a 500 foot high cinder cone located within the Bend city limits. == Oregon vents == The following vents are in Oregon: * Chamberlain Hill - Elevation 〔 * Cook's Butte - Elevation 〔 * Highland Butte - Elevation 〔 (near Beavercreek, Oregon) * Kelly Butte - Elevation 〔 (near the interchange of SE Powell Boulevard and I-205 in Portland) * Larch Mountain - Elevation 〔 * Powell Butte - Elevation * Rocky Butte - Elevation (stone tower with outstanding view of Portland) * Ross Mountain - Elevation 〔 * Swede Hill - Elevation 〔 * Mount Scott - Elevation 〔 (named for Harvey W. Scott)〔(【引用サイトリンク】title=The Boring Lava Field: Portland, Oregon )〕 * Mount Sylvania - Elevation * Mount Tabor - Elevation (center of a large multi-use Portland city park) * Mount Talbert - Elevation * TV Hill - Elevation 〔 * Walker Peak - Elevation 〔 〕 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「Boring Lava Field」の詳細全文を読む スポンサード リンク
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