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The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie between Santa Barbara and San Diego counties. They derive the name Transverse Ranges due to their east–west orientation, making them transverse to the general north–south orientation of most of California's coastal mountains. Most of the system lies in the California chaparral and woodlands ecoregion. Lower elevations are dominated by chaparral and scrubland, while higher elevations support large conifer forests. Most of the ranges in the system are fault blocks, and were uplifted by tectonic movements during the Cenozoic Era. West of Tejon Pass, the primary rock types are varied, with a mix of sedimentary, volcanic, and metamorphic rocks, while regions east of the pass are dominated by plutonic granitic and metasedimentary rocks. ==Geography== Most of the Transverse Ranges are bounded to the north and east by the San Andreas Fault, which separates the ranges from the California Coast Ranges and the Peninsular Ranges. Notable passes along the fault include Tejon Pass, Cajon Pass, and San Gorgonio Pass. Components of Transverse Ranges to the north of the fault include the Tehachapi Mountains and the San Bernardino Mountains. The western and southern boundaries are generally acknowledged to be the Pacific Ocean and various alluvial valleys and basins. Major passes not along the San Andreas Fault include Gaviota Pass, San Marcos Pass, the Conejo Grade, Newhall Pass, and Cahuenga Pass. The mountains are notable for being steep and difficult to traverse across. On its northern end, there are few passes that are sufficiently low or wide enough to accommodate significant volumes of traffic. This has resulted in situations where major cities are linked to the rest of the state by relatively few number of roads; for example, the vast majority of traffic between the Central Valley and the Los Angeles area is routed through Tejon Pass. This results in significant traffic issues throughout Southern California when a pass has to be shut down due to heavy snow or construction. Occasionally, such as Santa Barbara during the 2005 La Conchita landslide, major cities may be cut off from timely road access to the rest of Southern California. The Transverse Ranges manifest themselves as a series of roughly parallel ridges with an average height of . The ranges are dissected by young, steep streams of relatively low flow rate; as a result, there is high topographic relief throughout the range, and other than in marginal areas (e.g. the San Fernando Valley) and a few river valleys (such as Lockwood Valley and Big Bear Valley), there are no large, flat basins within the ranges. 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「Transverse Ranges」の詳細全文を読む スポンサード リンク
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