During the last Ice Age, the desert regions of San Bernardino County were wet and green. A large lake once existed near present-day Barstow, attracting a multitude of birds, animals, and, according to some scientists, early humans.
In the 1940s, amateur geologists discovered artifacts resembling primitive stone tools embedded in the shoreline sediments of an ancient Pleistocene-era lake called Lake Manix, which dried up 18,000 years ago.
In 1954, San Bernardino County archaeologist Ruth Simpson presented unearthed artifacts from the site to Louis Leakey, a famous scientist known for their discoveries of early man sites in Africa. In 1963, Leakey studied the site and concluded that the pieces of rock found at Calico “unquestionably” were human-made artifacts.
The area became known as the Calico Early Man Site. In 1980, geologists dated the rocks to be 200,000 years old using a uranium-thorium dating process, which sparked a debate among scientists.
Most anthropologists believe humans first migrated to North America between 12,000 to 14,000 years ago. No human remains have been found at the site, which has fueled opposing views as to whether the artifacts are truly man-made or caused by natural forces.
Skeptics argue that most of what has been found is likely the result of natural forces breaking stone as they tumbled from the mountains. However, many scientists believe the site may have served as a seasonal tool making location for early hunters.
Since 1972, the digging has been conducted by supervised volunteers, many from university archeology classes or members of the Friends of Calico Early Man Site support group.
The site is now under the jurisdiction of the Bureau of Land Management. It is officially recognized in the national Register of Historic Places as the Calico Mountains Archaeological Site.
The information in this historical feature was originally part of a video series produced by the Assessor-Recorder-County Clerk’s office.
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