Ciervo Hills Fossil Dunes

On the northeastern slopes of the Ciervo Hills are several small "fossil" sand dune areas. They may be relicts of beach dunes formed during the late Pliocene before the ocean receded from this portion of the San Joaquin Valley.

Vegetation here is notable for the number of species typical of the Mojave Desert and cismontane Southern California. Among these plants are Abronia pogonantha, Atriplex polycarpa, Caulanthus inflatus, Ephedra californica, Rumex hymenosepalus and Chaenactis fremontii. With the exception of the Ephedra and Atriplex, these species reach their northernmost cismontane distribution some 25 kilometers (15 miles) northwest at Panoche Gorge.

Vertebrates are typical of the inner Coastal Ranges; however, the insect population is unusual. There are several rare dune beetles, particularly the sand beetle, Coelus gracilis, that occur here. This species is apparently extinct at the type locality at Antioch Dunes, and is known from only two other localities. Aegialia concinna is known from only this area, and the very rare Vacronus tenuicornis occurs here and in three or four localities in Southern California.

Integrity: There is off-road-vehicle damage.

Use: Private

Ref: Doyen, J. T. and P. A. Opler, 1973. Distributional Affinities of Some Xerophilous Insects (Coleoptera, Lepidoptera) in Central California. Southwestern Naturalist 18 (3), pp. 305 - 316.

March 1980