The percentages of obsidian tools and debris remain generally similar to those in the Late Archaic level except that the counts are much higher (XFigure 3-7X). By count, obsidian tools are doubled, and obsidian debris is 4.3 times greater, and all the obsidian has visual characteristics of the Chivay type (Aldenderfer 1999).

Based on the density of obsidian, the relationship with the Chivay source area 221 km away seems to be well-established by this time, and it is a relationship that becomes even more well-developed in the Early Formative. Six samples of obsidian were analyzed at the MURR facility from Terminal Archaic contexts that are associated with a radiocarbon date of 3660±120 (Beta-43926; 2210-1880 BCE). All six obsidian samples were from the Chivay source.