A. Map boundaries: 30 to 40 degrees North; 110 to 120 degrees West
B. Countries (States): Mexico (Baja California, Sonora), United States (Arizona, California, Nevada, Utah).
C. Part II, The Cultural Landscape Expanded
This section provides an overview of National Historic Landmarks (NHLs) and other notable historic properties in the desert southwest. Part III contains a detailed listing of all sites.
The Prehistoric Landscape
Perhaps the most controversial of the sites is the Calico Early Man Site in the Mojave Desert near Barstow, California. It was made famous by Louis S.B.Leakey, the Kenyan anthropologist who discovered much evidence of early man in Africa. From 1964 until 1972, Leakey promoted the idea that the artifacts found in the American desert were similar to artifacts found in Africa. Leakey excavated an alluvial fan and considered the artifacts found to be the result of human activity. The age of the fan was believed to be over 50,000 years old (Leakey, Simpson, and Clements 1968). Today most professionally trained archaeologists question whether the alleged stone tools were manufactured by humans. However, Friends of Calico Early Man Site continues the tradition of investigating the site for evidence of early man (site 75 on map).
The prehistoric inhabitants of the Sonoran and Mojave Deserts left behind abundant archaeological evidence of their presence. Canals, trincheras sites, and rock art are three of the more notable cultural landscapes in the region. At the Pueblo Grande Museum and Archaeological Park in Phoenix, the largest canals known from pre-Columbian North America are preserved. Modern irrigated agriculture and suburban development has largely obliterated these canal systems. However, approximately 500 km of major canals and 1600 km of smaller canals have been recorded in the Salt River Valley. These canals were largely built between 900 and 1450 CE. The extensive canal system would easily have diverted all of the available Salt River water during dry periods, suggesting that some sort of coordination or control was necessary to allocate the water among all the systems in the Salt River Valley (Masse 1981).
Trincheras sites are distinguished by their locations on a hill or mountain peak and the use of massive stone terraces or walls. At the Cerro de Trincheras site in Sonora (site 76 on map), 900 massive stone-walled terraces cover the entire north side of a hill. There was a plaza on the summit and a public events area on the lower slope. Another notable trincheras site is Cerro Prieto 35 miles northwest of Tucson. Numerous small trincheras sites dot Sonora and southern Arizona. Desert Laboratory of the University of Arizona (see site 9 on map) is built on a trincheras site.
At the Coso Mountains in California, Big and Little Petroglyph Canyons (site 4 on map) contain the most spectacular petroglyph areas in the western US, with 20,000 designs showing bighorn sheep, deer, antelope. Along the canyon walls are anthropomorphic figures showing dogs attacking sheep and people hunting sheep. Piled rock statues are ‘dummy hunters’ of bighorn sheep. Another premier rock art site is Nine Mile Canyon in Utah. This canyon holds at least 10,000 images. Recently, heavy truck traffic through a dirt road in the canyon caused concerns about damage to the rock art panels. Of special concern was the use of magnesium chloride to suppress dust. This salt may corrode the rock and damage the paintings, according to art conservators (Kloor 2008).
The Emigrant Landscape
Sites important to the emigrant experience during the 1840s through the 1870s are common in this map area. Notable NHLs are the Yuma Crossing National Heritage Area (site 52), Mountain Meadows Massacre Site in Dixie National Forest (site 31), Warner Springs Ranch in southern California (site 50), and Walker Pass (site 49), providing a way between the California Desert and the Central Valley. The Oak Grove Butterfield Stage Station in southern California (site 34) is also a NHL. Further north are sites on the California Trail and Pony Express Trail such as Fort Churchill (site 14) and Carson Pass. Early mining towns such as Virginia City (site 48) and Bodie (site 5) are well-preserved, and perhaps most famous of all, Tombstone (site 45) is the best-preserved frontier town, located in southeastern Arizona. Early Spanish settlement is commemorated through the system of missions in Arizona and California, as well as Mexican adobe houses and ranches dating from the early 1800s.
The Tourism Landscape
Sites at Bryce Canyon, Grand Canyon, and Yosemite have been designated as National Historic Landmarks because of the distinctive “‘national park rustic resort style.” Facilities at Bryce Canyon and Grand Canyon were constructed by railroads. Grand Canyon Village was the largest town developed by the National Park Service to meet thee needs of visitors and park staff. The visitor center at Tucumcori National Monument (site 29) was built in mission revival architecture to serve as an interpretive device. Balboa City Park in San Diego was constructed for the 1915 Panama-Canal Exposition and includes Spanish baroque architecture. Today it is the center of the city’s museum district. Nearby Mission Beach Roller Coaster was listed as an early 20th century recreational development, as was the Loof Hippodrome and carousel at the Santa Monica Pier (site 11). The Hotel del Coronado near San Diego (site 8) is considered to be the most architecturally interesting luxury hotel in the U.S., and Mission Inn in Riverside (site 20) is another late 19th century luxury hotel listed as a NHL.
The Science and Technology Landscape
Three nineteenth century sites important to the science of plant ecology are on the NHL list in Arizona. The C. Hart Merriam Base Camp on the Coconino National Forest (site 28) was where the Life Zone Concept was formulated. The Desert Botanical Laboratory west of Tucson (site 9) was where the science of plant ecology was born. At the Lowell Observatory in Flagstaff (site 26), the science of dendrochronology was born.
Sites important to astronomy are on the NHL list in Pasadena. These include the Jet Propulsion Laboratory and its on-site space simulator and the houses of some of America’s greatest astronomers, Edwin Hubble and Ellery Hale (site 17). Nearby, overlooking Pasadena, is the Mount Wilson Observatory. Also important in the unmanned exploration of space was the Pioneer Deep Space Station antenna in the California Desert (site 37). The Rogers Dry Lake at Edwards Air Force Base (site 38) has been used for aircraft flight testing since 1933 and was a landing spot for the Space Shuttle. Aircraft first broke the sound barrier here. Other important astronomical discoveries were made at the Lowell Observatory in Flagstaff, where it was determined that the universe continues to expand. The tops of mountains in the sky islands of Arizona and southern California continue to attract astronomical observatories. Notable current facilities are Kitt Peak (site 58) and Whipple (site 111) Observatories in Arizona and Mount Wilson and Palomar (site 34) in California.
Large government-sponsored water works have been essential to the development and growth of the desert regions. Historic civil engineering landmarks highlight some of these facilities. The Los Angeles Aqueduct, which carries water from northern California near Mono Lake, and the Colorado River Aqueduct, which carries water from the east, are landmarks, as is the Salt River Project supplying water to central Arizona. No list of water infrastructure would be complete without including the Hoover Dam (site 22), one of the greatest achievements in hydraulic engineering.
D. Terrestrial Ecoregions
Ecoregions of the Neararctic Biome
Tropical & Subtropical Coniferous Forests
NA 302, Sierra Madre Occidental pine-oak forests. These forests occur as isolated sky islands on mountain peaks between 1500 and 3,300 m in elevation. Drier areas have chaparral and oak-grassland vegetation. The region is known for endemic birds such as the thick-billed parrot, tufted jay, eared quetzal, and green-striped brush finch; 22 endemic reptiles; and 12 endemic amphibians. The mountain air currents are a major migratory pathway for the monarch butterfly. Found in Arizona and Sonora.
Temperate Coniferous Forests
NA 503, Arizona Mountains forests. Ponderosa pine forests predominate in open park-like areas. Above 2000 m are Douglas-fir and spruce. Found in Arizona.
NA515, Great Basin montane forests. At high elevations, forests of white fir, limber pine, and bristlecone pine are found at timberline. Found in California and Nevada.
NA526, Sierra Juarez and San Pedro Martir pine-oak forests. Two mountain ranges support pine and fir forests in a Mediterranean climate regime of winter rains. There are ten species of pine. Found in Baja California.
NA527, Sierra Nevada forests. The most diverse temperate coniferous forests on Earth support numerous species of pine and 75 giant sequoia groves. Found in California and Nevada.
NA530, Wasatch and Uinta montane forests. Ponderosa pine, Douglas-fir, subalpine fir, and Gambel oak are found in sparse, arid forests on Utah mountaintops. The southernmost extensions of this area shown on the map tend to be high plateaus. Found in Utah.
Temperate Grasslands, Savannas and Shrublands
NA801, California Central Valley grasslands. Perennial bunchgrass ecosystem and oak-grass savanna grade into desert grasslands in the south. Extensive mass flowerings of California poppy and other wildflowers are characteristic. Vernal pools are found in flooded depressions. Found in California.
Mediterranean Forests, Woodland, and Scrub
NA 1201, California coastal sage and chaparral. The fire-adapted coastal sage and chaparral plants are interspersed with oak woodlands. Higher elevations support pine forests. Found in Baja California and California.
NA 1202, California interior chaparral and woodlands. A zone of oak woodland and chaparral rings the Central Valley grasslands. Found in California.
NA1203, California montane chaparral and woodlands. The southern extension of the Sierra Nevada and the mountains surrounding the Los Angeles basin have plant communities consisting of chaparral, pinyon-juniper, oak woodlands, and pine forests. Found in California.
Deserts & Xeric Shrublands
NA 1301, Baja California desert. The mountains, plains, and dunes host xeric scrub of cacti, Ambrosia, and Erodium. In low humid areas epiphytes are present. Endemic mammals include the San Quintin kangaroo rat and Baja California rock squirrel. Found on the western side of the Baja California peninsula in Baja California.
NA 1303, Chihuahuan desert. This isolated desert and grassland is known for prairie dog, bison, and antelope. The dominant plant is creosote bush, along with tarbush and acacia. There are up to 1,000 endemic plant species, including one-fifth of the world’s cacti. Found in deep valleys reaching into the mountains of eastern Sonora and southeastern Arizona.
NA 1304, Colorado Plateau shrublands. Characterized by extensive and sparse pinyon pine and juniper woodlands. Found in Arizona, Nevada, and Utah.
NA1305, Great Basin shrub steppe. Characterized by sagebrush, saltbush and winterfat. Called a shrub steppe because of the absence of grasses. Found in California, Nevada, and Utah.
NA1308, Mojave Desert. Characterized by creosote bush and Joshua trees. Found in Arizona, California, Nevada, and Utah.
NA 1310, Sonoran Desert. The desert most famous for the saguaro cactus also contains creosote bush, ironwood, palo verde and other cacti in drier areas. Found in Arizona, Baja California, California, and Sonora.
E. World Heritage Sites
Grand Canyon National Park, Arizona. Terrestrial ecoregions NA503 and NA1304. The Tusayan ruin, including a small pueblo site, is on the South Rim. National Historic Landmarks include the four Mary Jane Colter Buildings, Grand Canyon Depot, Grand Canyon Lodge, Grand Canyon National Park Operations Building, Grand Canyon Power House, Grand Canyon Village, and El Tovar Hotel (site 7 on map).
Islands and Protected Areas of the Gulf of California (IPAGC). This includes nine protected area units, two of which are within the map area. The two units shown on the map are:
- Islands of the Gulf of California Flora and Fauna Reserve (IGCFFR), Baja California and Sonora. This includes 232 islands, nine of which fall within the map area. Terrestrial ecoregion NA 1310; marine ecoregion 60.
- Upper Gulf of California and Colorado Delta Biosphere Reserve, Baja California and Sonora. Includes the former outlet of the Colorado River. Terrestrial ecoregion NA1310; marine ecoregion 60.
Yosemite National Park, California. The Ahwahnee Resort Hotel, Leconte Lodge, and Ranger’s Club in Yosemite Valley, the Wawona Hotel and Thomas Hill Studio in Wawona, and Parsons Memorial Lodge in Tuolumne Meadows are National Historic Landmarks (site 1 on map). Ecoregion NA527.
F. Further Reading
Durham, Michael S. 1990. The Smithsonian Guide to Historic America: The Desert States. Stewart, Tabori and Chang, New York.
Garfinkel, Alan P. 2006. Paradigm Shifts, Rock Art Studies, and the “Coso Sheep Cult” of Eastern California. North American Archaeologist 27:203-244.
Kloor, Keith. 2008. Dust Storm Rising Over Threat to Famed Rock Art in Utah. Science 319:394.
Leakey, L.S.B., Ruth de Ette Simpson, and Thomas Clements. 1968. Archaeological Excavations in the Calico Mountains, California: Preliminary Report. Science 160:1022-1023.
Logan, William Bryant and Susan Ochshorn. 1989. The Smithsonian Guide to Historic America: The Pacific States. Stewart, Tabori and Chang, New York.
Masse, W. Bruce. 1981. Prehistoric Irrigation Systems in the Salt River Valley, Arizona. Science 214:408-415.
Noble, John et al. 2010. Mexico. Lonely Planet Publications.
Pueblo Grande Museum and Archaeological Park. http://phoenix.gov/recreation/arts/museums/pueblo/index.html (accessed October 29, 2011).
UNESCO-Man and the Biosphere Reserves Directory. http://www.unesco.org/mabdb/br/brdir/directory/database.asp (accessed 5/30/11).
Warner Springs Ranch. http://www.warnersprings.com/history.cfm (accessed 11/1/11)
World Heritage List. http://whc.unesco.org/en/list (accessed 5/22/11).