This subsection consists of the lake plain around Mono Lake, which is at the base of the steep eastern slope of the Sierra Nevada.  It has a temperate, semi-arid climate.  MLRA 26f.

Lithology and Stratigraphy.  Pleistocene and recent lacustrine deposits predominate in this subsection.  There is some recent andesite and pyroclastics from volcanoes on Paoha and Negit Islands in Mono Lake and at Black Point on the north shore of the lake.

Geomorphology.   The landform is mostly nearly level to gently sloping lake plain.   Mono Valley is slightly elongated toward the northeast.  The lake plain slopes southwest, so Mono Lake is at  the southwest end of the valley.  A sequence of several old beach ridges is evident on the northeast side of the valley.  The elevation range is from about 6400 feet at the present lake level up to 7180 feet at the highest Pleistocene lake level.   The present lake is saline and alkaline, containing about 6% salt.  Tufa mounds are prominent features around the lake.  Lacustrine deposition and volcanism are the main geomorphic processes.

Soils.  The soils are mostly Xeric Torripsamments and Torriorthents, Haploxerollic Durorthids, and Xerollic Haplargids.  There are also shallow Xerollic Durargids and Abruptic Durixeralfs on volcanic rocks.  The soils are well drained.  Soil temperature regimes are mesic; and soil moisture regimes are aridic.

Vegetation.   The predominant natural plant communities are Big sagebrush series and some Singleleaf pinyon series and Bitterbrush series.  Greasewood series occurs in seep areas.

Characteristic series by lifeform include:

Grasslands: Alkali sacaton  series, Ashy ryegrass series, Creeping ryegrass series, Indian ricegrass series, Needle-and-thread series, Saltgrass series.

Shrublands: Allscale series, Bush seepweed series, Mixed saltbush series, Rubber rabbitbrush series, Shadscale series.

Forests and woodlands: Singleleaf pinyon series.

Surface Water.  Mono Lake is in a closed basin that was occupied by Pleistocene Lake Russell.  The maximum height of the lake, 7810 feet, was controlled by overflow into Adobe Valley.   Much water from Sierra Nevada streams which flow to Mono Lake has been diverted for municipal use, lowering the lake level.  Recent regulation of water diversion has halted the decline in lake level.