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Lithology and Stratigraphy. This subsection contains mostly Mesozoic granitic and Pre-Cenozoic metamorphic rocks. There is some Pleistocene sediment and Recent alluvium and small areas of Miocene volcanic rocks and Miocene and Pliocene nonmarine sediments.
Geomorphology. This is a subsection of moderately steep to steep mountains with narrow to rounded summits and both narrow canyons and broad valleys. There are small areas of rolling plateau. The valleys are occupied by Pleistocene to Recent alluvial fans. The subsection elevation range is from about 300 feet up to 5261 feet on Asbestos Mountain. Mass wasting and fluvial erosion and deposition are the main geomorphic processes.
Soils. The soils are mostly Lithic and shallow Typic Xerorthents, Lithic Xerochrepts, Haploxerolls, and Mollic Haploxeralfs. In badland areas at lower elevations, they are mostly shallow Typic Torriorthents and Typic Camborthids. The soils on alluvial fans are mostly Typic Torrifluvents, Torripsamments, Typic Toriorthents, and Typic Haplargids. Carbonates accumulate in the soils. They are well drained. The soil temperature regimes are mostly thermic. Soil moisture regimes are xeric (nearly aridic) and aridic.
Vegetation. The natural plant communities are mostly Creosote bush series and Creosote bush - white bursage series, Chamise series and Red shank - chamise series, Mixed chaparral shrublands, Singleleaf pinyon series, and California juniper series.
Surface Water. Runoff is rapid. The streams are dry through the summer. They drain to the Salton Trough or sink into the ground before reaching the Salton Trough. There are no lakes in the subsection.
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