Subsection M262Ag
Kettleman Hills and Valleys

Lithology and Stratigraphy.  This subsection is dominated by an anticline with a core of upper Miocene and Pliocene marine sediments.   Individual sections of the anticline are domes with rings of Plio-Pleistocene nonmarine sediments around the margins.  A synclinal basin between anticlines is filled with Quaternary alluvium.

Geomorphology.  This subsection is dominated by a low, discontinuous, northwest trending ridge that is an anticline.  The discontinuous form of the ridge is reflected in the name - that is, Kettleman Hills, rather than Kettleman Ridge.  Pleistocene nonmarine sediments  and recent alluvial fan deposits have created a flat apron around the Kettleman Hills and a flat floor in Pleasant Valley and on Kettleman Plain.  The elevation range is from about 500 to 600 feet on the fans up to about 1200 feet on the hills. Fluvial erosion and deposition are the main geomorphic process.

Soils.  The soils are mostly Typic and Lithic Torriorthents on upper Miocene and Pliocene marine sediments; Typic Camborthids, Typic Halargids, and Typic Natrargids on Plio-Pleistocene nonmarine sediments; calcareous Typic Torrifluvents and Typic Torriorthents on Pleistocene nonmarine sediments; and Typic Torriorthents and Typic Haplargids on recent alluvial fans.  Calcium carbonate accumulates in the subsoils, and more soluble salts accumulate in some of the soils.  The soils are well drained.  Soil temperature regimes are thermic.   Soil moisture regimes are aridic.

Vegetation.   The predominant natural plant community is the California annual grassland series.

Characteristic series by lifeform include:
Grasslands: California annual grassland series, Saltgrass series.
Shrublands: Allscale series, Arrow weed series, Bladderpod - California ephedra - narrowleaf goldenbush series, California sagebrush series, Fourwing saltbrush series, Shadescale series, Spinescale series.

Surface Water.  Runoff is rapid and local streams are dry before summer.  Streams originating in mountains west of the Kettleman Hills have water longer into the dry season, but even they dry up during the summer.  There are no lakes in the area.