The Calico Early Man site, located east of Barstow, California, has been an archaeological site of some distinction ever since Louis Leakey visited it in 1964 shortly after its discovery. Although no human remains such as bone or teeth have been unearthed as yet, over 60,000 tools and flakes have been collected. Most of these are kept in the San Bernardino County Museum under the watchful eye of Ruth Simpson, Museum Director and archaeologist. There exists a debate over whether the artifacts were made naturally or by the hand of man. Many experts in the scientific community are now convinced of the authenticity of the site.
The latest dating of the alluvial deposit where the implements reside has been set at 135,000 years old! This establishes the approximate geological date of the artifact-bearing level. You might say, "Sure, the geologic level may be that old but how do you know when the tools were actually made?" Good question! In 1981 scientists Ku and Bischoff used the uranium-thorium method to yield a date of 200,000 years (+/- 20,000) for the artifacts at the bottom of the geologic level in question. The topmost soil layer was estimated at 100,000 years. Therefore, the artifacts which were made and then covered over by later deposits have to be older than the youngest layer above them. Fred Budinger, assistant director of the site, says that this "new date is scientifically important because it provides a second independent age assessment of these beds."
This date is unusual because it is believed that the first people arrived in North America during the last ice-age, approximately 20,000 - 30,000 years ago, crossing the land-bridge at the Bering Sound, from northeastern Siberia into Alaska. The oldest documented human cultures in North America are Sandia (15000 BC), Clovis (12000 BC) and Folsom (8000 BC).