Point Sal Area
Map SatelliteThis area, which runs from Shuman Canyon on the south to Point Sal and Mussel Rock, contains a variety of plant communities as well as being of particular geologic interest. much of the area is covered by grassland, with some natives such as Stipa lepida (=Nassella sp.) and Nassella pulchra, but, for the most part, introduced annuals. Two phases of coastal sage scrub are found here. In the dominant phase, California sagebrush, Artemisia californica, and black sage, Salvia mellifera, are primary components. On some of the ridges there is the purple sage phase, with Salvia leucophylla making up more than 50% of the ground cover and Artemisia californica and Encelia californica another 25 to 35%. Leymus condensatus and Baccharis pilularis also occur in this phase.
In Shuman Canyon there is a small amount of riparian woodland with black cottonwood, Populus trichocarpa, and Salix lasiandra the most conspicuous elements. There is also some coastal strand together with dunes. Along Shuman Creek there is a small amount of freshwater and saltwater marsh. Coastal dunes border the intermittent creek which empties directly into the ocean .
Among the more noteworthy plants in the area are Malacothrix incana var. succulenta [Ed. note: Malacothrix incana var. succulenta not recognized], the rare species Senecio blochmaniae, Castilleja mollis and Scrophularia atrata. The giant coreopsis, Coreopsis gigantea, is not uncommon in the area.
The terrestrial fauna is varied and includes species typical of the central coastal region. The legless lizard, Anniella pulchra, is found in the dunes area, as are several insects. The exposed rocky coastline around Point Sal and southward supports a rich assemblage of marine vertebrates and invertebrates (see Point Sal State Beach).
The geology is quite varied and the rocky cliffs give excellent exposures of the various rocks. At the Point, a Jurassic shale rests on Franciscan volcanic and metavolcanic rocks. Most of these Franciscan rocks are pillow lavas, the result of the rapid cooling of the volcanic extrusions in cold sea water. The amygdules of quartz and epidote are found in this pillow basalt, as are dikes of andasite and diabase. Below the basalt is a diabase mass grading to gabbro, which is covered by Tertiary deposits in places. However, the gabbro crops out south of these deposits and here is fairly uniform; as this belt extends further southeast the gabbro becomes banded with layers of diorite and hornblende gabbro.
Further along the coast, and presumably lower in the sequence, are olivine pyroxenite, anorthosite, hypersthene gabbro, serpentinized peridotite and serpentinized dunite. In the southern part of the area the serpentine forms a precipitous outcrop known as Lions Head, which rises some 120 meters (400 feet) above the water. This ultramaficmafic succession is similar to the ophiolite found elsewhere in the Coast Ranges and may very well represent a section of the Mesozoic oceanic crust. There are several Pleistocene marine terraces in evidence in the area.
Integrity: A portion of the area has been grazed. There are roads in the area as well as a railroad, but most of the area is virtually undisturbed.
Use: Restricted. Portions are private.
Ref: Coulombe, H. and C. F. Cooper, 1975. Ecological Assessment of Vandenberg Air Force Base, Calif. Vol. I and II, A.F. Civil Eng. Cent. Tyndall Air Force Base, Florida, 189 pp. and 201 pp.
Bailey, E. H., M. C. Blake and D. L. Jones, 1970. Onland Mesozoic Oceanic Crust in California Coast Ranges. U.S. Geol. Surv. Prof. Paper 700-C, pp. C70-C81
March 1977
Inventory of California Natural Areas
Revision © 2009 Steven Louis Hartman
