Subsection 342Bb
Sheldon Range

Geomorphology.   Gently to moderately sloping plateau with few moderately steep hills predominates in this subsection.  The fault-line scarp on the eastern edge of Mount Bidwell, which is on the western margin of the subsection, is steep.  The plateau lacks a well integrated drainage system; there are many small closed depressions.   The elevation range is about 4500 to 6000 feet on the plateau and up to 8000 feet on a  fault-line scarp along the western edge of the subsection.  Fluvial erosion and deposition and freeze-thaw are the main geomorphic processes.  Volcanism is no longer an active process.

Soils.  Soils are mostly Lithic Xerollic Haplargids, Lithic and Pachic Argixerolls, Xerollic Natrargids, Abruptic Xerollic Durargids, and Pachic and Argic Cryoborolls.  The soils are well drained.  Soil temperature regimes are mostly frigid and cryic, but mesic around the alluvial plain in Surprise Valley.  Soil moisture regimes are mostly aridic and  xeric.

Vegetation.   The predominant natural plant community is Big sagebrush series.  Shadscale series occurs in the drier areas.  Rubber rabbitbrush series occurs on disturbed sites.

Characteristic series by lifeform include:
Grasslands: Ashy ryegrass series, Bluebunch wheatgrass series, Creeping ryegrass series, Indian ricegrass series, Needle-and-thread series.
Shrublands: Big sagebrush series, Bitterbrush series, Low rabbitbrush series, Rubber rabbitbrush series.
Forests and woodlands: Curlleaf mountain-mahogany series.

Surface Water.  Runoff from uplands is rapid, but water ponds in small depressions.   Most of the drainage is internal, to closed depressions in the subsection.  There are few streams and most of those are dry during summer.