Eureka Valley

The southern end of Eureka Valley, the eastern slopes of the Saline Range and the Last Chance Mountains eastward to Death Valley are included in this area.

Eureka Valley is a small basin which was a lake during the Pleistocene. Remnants are found in the playa silts and clays and in the sand dunes (see Eureka Dunes).

The dominant vegetation on the valley floor and the lower slopes of the adjacent ranges is a creosote bush scrub with Larrea tridentata and Psorothamnus polydenius, though Atriplex polycarpa is dominant near the dunes. Occasionally there are excellent displays of wildflowers in the spring. Some of the alluvial fans support a variety of cacti.

On the higher portions of the Last Chance Range there is a pinyon-juniper woodland, primarily with single-leaved pinyon, Pinus monophylla, but with some Utah juniper, Juniperus osteosperma. Below this woodland there is a sparsely developed Joshua tree woodland.

A number of rare or uncommon plants are found in the area, including Astragalus lentiginosus var. micans, Buddleja utahensis, Cymopterus deserticola, Hecastocleis shockleyi, Mimulus rupicola, Stanleya pinnata ssp. inyoensis, and Swallenia alexandrae. The limestone outcrops support a variety of unique species including the rare Penstemon calcareus.

A number of plants show Death Valley and southern affinities, but Chaetadelphia wheeleri may be at its southern limit here.

Due to the extreme aridity of the area, animal life is not particularly abundant, though various mammals, including coyotes, Canis latrans, and jack rabbits, Lepus californicus, various small rodents, birds and reptiles have been observed. There are several insects endemic to the dunes.

Geological formations found in the area include Cambrian and Ordovician dolomites, limestones and quartzite, Mississippian metasedimentaries, Tertiary rhyolites (primarily in the Last Chance Mountains), Pliocene volcanics (in both ranges) and Pleistocene non-marine deposits. Much of Saline Range is composed of the volcanics.

Integrity: While the dunes and some of the adjacent area have suffered off-road-vehicle damage, most of the area is undisturbed. It has been proposed for a Wilderness.

Use: Research, educational, observational.

Ref: DeDecker, Mary, 1976. The Eureka Dunes. Fremontia 3 (4), pp. 17 - 20.

March 1980