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| range = Western Cascades | location = Jackson County, Oregon, United States | map = USA Oregon | region_code = US-OR | source = NGS | map_caption = Location in Oregon | label_position = right | map_size = 250 | lat_d = 42.354992364 | long_d = -122.785277725 | coordinates_ref = | topo = USGS Medford East | type = | age = | volcanic_arc = Cascade Volcanic Arc | easiest_route = Hike }} Roxy Ann Peak is a mountain in the Western Cascade Range at the eastern edge of Medford, Oregon. Composed of several geologic layers, the majority of the peak is of volcanic origin and dates to the early Oligocene. It is primarily covered by oak savanna and open grassland on its lower slopes, and mixed coniferous forest on its upper slopes and summit. Despite the peak's relatively small topographic prominence of , it rises above Medford and is visible from most of the Rogue Valley. The mountain is Medford's most important viewshed, open space reserve, and recreational resource. The peak was originally settled 8,000 to 10,000 years ago by ancestors of the Latgawa Native American tribe. In the early 1850s, a sudden influx of non-indigenous settlers resulted in the Rogue River Wars. After the wars, the Latgawa were forced away from the region onto reservations. The peak was named in the late 1850s after one of its first landowners, Roxy Ann Bowen. In 1883, the city of Medford was established to the west of the mountain, and became incorporated two years later. After acquiring a large amount of land from the Lions Club and the federal government between 1930 and 1933, the city created the Prescott Park in 1937. The park protects much of the upper slopes and summit of the peak and remains largely undeveloped. The peak's southern foothills have some quickly expanding single-family residential subdivisions. ==Geology== Roxy Ann Peak is part of the old and deeply eroded Western Cascades, along with nearby Pilot Rock, Grizzly Peak, and Baldy. It is composed of several distinct geologic layers. The oldest layer, the 35- to 50-million-year-old Payne Cliffs Formation, forms the base of the peak and consists of sedimentary sandstone, shale, and conglomerates. Most of the rest of the mountain is made up of 30- to 35-million-year-old volcanic basalt, breccias, and agglomerates, known as the Roxy Formation. These rocks are some of the oldest in the Cascades. At the summit, younger basalt dikes and intrusions K–Ar dated to 30.82 ± 2 million years ago form a relatively erosion-resistant cap, likely contributing to the peak's isolation and familiar conical shape. Much of the lower slopes of Roxy Ann are covered by a layer of dense, sticky clay. Due to the clay's low shear strength, the soil is prone to creep, earthflows, and landslides. Several large subdivisions lie on top of these deposits, some of which are up to thick. The peak stands above sea level with a topographic prominence of , and rises above the surrounding Rogue Valley. The unique rounded top, location, and height of the peak create a landmark distinguishable from as far away as Shady Cove, to the north, and the Siskiyou Summit, to the south. 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「Roxy Ann Peak」の詳細全文を読む スポンサード リンク
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