Geology, Flora and Fauna

The San Gorgonio Wilderness is home to several distinct biotic communities. These include: chaparral, yellow-pine forest, montane meadows, lodgepole forest, sub-alpine and alpine fell.

During the Pleistocene period, the Wilderness was home to at least seven cirque and valley glaciers heading at elevations between 10,300 and 11,300 and ranging from ½ mile to 1 ¾ miles in length. None descended below 8,700 feet. Today, one can identify the ancient glaciation by obvious cirques and large medial and terminal moraines up to 700 feet in height, one of which formed Dollar Lake.
dollar_lake1

Common Rock Types:

Muscovite Biotite Gneiss
muscovite biotite gneiss
Location: Grinnell Mountain
Age: Proterozoic (1.76 billion years)
Description: A metamorphic rock with well-developed, planar layering and linear fabric, typical of rocks on the slopes north of Dry Lake, San Gorgonio Wilderness.
Muscovite Biotite Migmatitic Gneiss
muscovite biotite migmatitic gneiss
Location: San Gorgonio Mountain
Age: Uncertain, probably Cretaceous (80 million years)
Description: A metamorphic rock with well-developed, convolute layering, cut by light tan granite dikes, typical of rocks on the north slope of San
Gorgonio Mountain, San Gorgonio Wilderness.
Muscovite Biotite Granite
muscovite biotite granite
Location: San Gorgonio Mountain
Age: Uncertain, probably Cretaceous (80 million years)
Description: An igneous rock without visible layering, typical of rocks
along the summit ridge of San Gorgonio Mountain, San Gorgonio Wilderness.

Mammals:

Chipmunk Tamias spp.(species unidentified)
Golden-mantled Ground Squirrel, Spermophilus lateralis
Western Gray Squirrel , Sciurus griseus
Black Bear, Ursus americanus
Bighorn Sheep, Ovis canadensis nelsoni
Mountain Lion, Felis concolor
Coyote, Canis latrans
Mule Deer Odocoileus hemionus

Trees:

Black Oak, Quercus kelloggi
Mountain Mahogany, Cercocarpus ledifolius
Coulter Pine, Pinus coulteri
White Fir, Abies concolor
Limber Pine, Pinus flexilis
Lodgepole Pine, Pinus contorta
Jeffrey Pine, Pinus jeffreyi
Ponderosa Pine, Pinus ponderosa
Incense Cedar, Calocedrus decurrens
Sugar Pine, Pinus lambertiana
Black Cottonwood, Populus trichocarpa
Quaking Aspen, Populus tremuloides

Shrubs and other plants:

Bracken Fern (Pteridium aquilinum)
Manzanita (Arctostaphylos spp.)
Chinquapin
Scrub Oak
Willow
Stinging Nettle
Whitethorn
Wild Buckwheat
Elderberry
Wax Current
Sierra Gooseberry
Rabbitbrush
Yucca
Sedges
Bush Monkeyflower
Miner’s Lettuce
Coffeeberry
Wild Rose