Analysis of 3,500+ stone flakes shows tool-making patterns at Calico. 26% of flakes showed clear bulbs of percussion from deliberate stone striking 70% had no cortex, suggesting they'd been worked down through multiple stages Nearly half showed multiple facets on upper surface, evidence of systematic flake removal

Excavations at Calico yielded lithic artifacts. Analysis found some showing percussion bulbs (evidence of deliberate striking), some preworked, and others showing systematic flake removal. Nearby control pits contained much less by comparison. Is this human craftsmanship or nature at work?

Key findings reported:

- 26% of flakes showed clear bulbs of percussion from deliberate stone striking

- 70% had no cortex, suggesting they'd been worked down through multiple stages

- Nearly half showed multiple facets on upper surface, evidence of systematic flake removal

- One refitted core was found with flakes that fit back together perfectly

- One excavation unit alone produced over 1,000 fragments

Note: These findings remain contested. Critics argue natural processes such as freeze-thaw cycles, river transport, and geological pressure can produce similar flake characteristics, including pseudo-bulbs and apparent percussion marks. The Calico site has been subject to ongoing scholarly debate regarding the anthropogenic origin of its lithic assemblage.

Key Facts

  • 26% of flakes showed clear bulbs of percussion from deliberate stone striking
  • 70% had no cortex, suggesting they'd been worked down through multiple stages
  • Nearly half showed multiple facets on upper surface, evidence of systematic flake removal
  • One refitted core was found with flakes that fit back together perfectly
  • One excavation unit alone produced over 1,000 fragments
  • Control pits nearby found almost nothing, a few dozen pieces at most
  • Master pits had hundreds of times more material than surrounding zones
  • Around 80% of specimens kept good edges, some sharp enough to cut skin during excavation

Related site: Calico Early Man Site — view location, images, and history on the Ancient Nerds map.

Source: This Discovery in America Destroys the Timeline by Michael Button