About the Calico Early Man Site

About the Site

The Calico Early Man Site which includes about 900 acres in the central Mojave Desert, just 16 miles east of Barstow. Less than 20,000 years ago, a person standing in the Calico Mountains would look south and east and see a huge lake surrounded by sandy beaches, marshes and mud flats.

Today, the lake is dry, and the arid environment supports catclaw, mesquite and cacti including varieties of Opuntia such as beavertail and cholla. Creosote and brittle bush are the most common desert bushes in the district. The district supports over 80 species of desert flowers and numerous species of grasses, herbs and gourds. Most of the birds are adapted to arid conditions. Numerous reptiles are in the district, including the protected desert tortoise and the dangerous rattlesnake and sidewinder. The bobcat and coyote are the largest mammals.

The Calico Site includes the Dorothy Bowers Nature Trail. This easy, less than 2-mile trail has a printed guide to introduce the visitor to the landscape around the Calico Site as it is today. The stops along the trail are focused on some aspect of the environment, ranging from “desert pavement” to arid plant and animal life.

The Calico Site is located on an alluvial fan above Pleistocene Lake Manix, at an elevation of 2,200 feet. The prehistoric people who occupied the site probably made use of the lake’s abundant resources. The site has been excavated continuously since 1964. It is the only site that Dr. Louis Leakey, of Olduvai Gorge, Africa fame, ever worked on in the United States.

The Lake Manix Lithic Industry

The Lake Manix Lithic Industry is the name given to the stone tool technology in prehistoric archaeology sites that surround Pleistocene Lake Manix. The last stand of Lake Manix was around 18,000 years ago, and Calico may date to that time; however, recent cation-ratio and accelerator radiocarbon dating on Lake Manix surface artifacts at CA-SBR-2223 yielded dates between 1,700 to 7,200 years ago and artifacts from CA-SBR-2100 yielded dates from 300 to 21,900 years ago.

Before 18,000 years ago, the climate was much more wet than it is today. The lake shore consisted of marshes, mud flats and open sandy beaches. Alluvial fans around the lake probably were covered with juniper, sagebrush, creosote bushes and related plants. Within the basin, grassy areas were scarce and patchy.

When the lake was full of water, the air would have been filled with storks, pelicans and flamingos; and bison and other large animals would have been foraging along the lake shores.

The fossils remains of the Mojave tui chub, various fresh-water clams, fresh-water snails and the western pond turtle attest to the limits and nature of the lake. About 80% of the fossil birds lived on or preferred to feed on small fish; about 20% fed on water plants or fresh water clams. Among the fossil birds are pelicans, storks, flamingos, swans, geese, ducks, gulls and eagles. The fossils of large mammals are the remains of animals that died near the lake margin. Carnivores and water action separated and scattered these skeletons, but a few bones were quickly buried by soft lake mud. Subsequent mineralization preserved these bones as fossils. Among the fossils are ground sloths, mammoths, dire wolves, coyotes, bears, mountain lions, scimitar cats, horses, camels, llamas, antelopes, mountain sheep and bison. Jackrabbits and mice are the only small mammals known as fossils.

Site Dating

The datings of the site are geological dates; not dates of a cultural component. At the Calico Site’s Master Pit I, sediments have been dated to 135,000 and 204,827 years ago, and the “rock ring” (which was not a fire hearth) from Master Pit II had 8 TL dates ranging from 12,000 years ago to 80,000 years ago. The five surface geological samples were dated to between 57,000 and 148,000 years ago. At Ritner’s Ridge, dates of 203,000 years ago, 193,000 years ago, and 260,000 years ago were obtained. In the Rock Wren pit, a biface (stone tool) was recovered in a sediment that yielded a date of 14,400 years ago. But, these are all geological dates, and hence, date only the geology; the cultural component has never been dated. A date of 250+/-40 BP was obtained on a shaft attached to an arrow point, but the artifact was found on a bentonite pile near the Visitor’s Center. It was not found in the Master Pits.

The Calico Site is a quarry and tool production site on an alluvial fan, where chalcedony and chert were found in abundance. Many prehistoric tools were made from these rocks. No human remains or features and a minimal amount of ground stone have been found in the site’s deposits. The three master pits are almost 26 feet deep and show the geology of the alluvial fan, but entrance to the master pits is not allowed. Instead, they can be viewed from the top.


The site is closed to visitors, students and researchers. The Friends of Calico are no longer a viable association. This site references The Friends of Calico Early Man Site as a historical reference.