River Pines Peridotite Area
Map SatelliteOn this peridotite intrusion, which has weathered to serpentine and serpentine-derived soils, is another "ecological island" in the Sierra foothills. (See Ione Clay Barrens).
Much of the area is chaparral, with whiteleaf manzanita, Arctostaphylos viscida, and buck brush, Ceanothus cuneatus, dominant on the north slopes and ridge tops, and chamise, Adenostoma fasciculatum, on the south slopes. Gray pine, Pinus sabiniana, is scattered throughout. A ponderosa pine forest surrounds the area.
This area is the southernmost limit for several species in the Sierra, including the chaparral pea, Pickeringia montana, and MacNab cypress, Cupressus macnabiana. On the ridge and north slope are some of the largest known specimens of the cypress which occur here in a disjunct population some 88 kilometers (55 miles) south of the nearest grove. The rare Eriogonum tripodum is here at its northernmost-known limit.
The Mesozoic ultrabasic intrusion is surrounded by Mesozoic granites of the Sierra batholith and Paleozoic metavolcanics.
Integrity: There are several mines in the area, and housing developments may impinge upon the area.
Use: Private
March 1976
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman