Researchers have made a surprise discovery at the well-known Cave Creek Midden site in the desert upland of southeast Arizona, close to the border with Mexico - a 3,000-year-old bison kill site featuring hundreds of bones and bone fragments, along with dozens of cobblestones and flaked and ground stone tools.
     First investigated in 1936, the site revealed stone tools and other artefacts typifying a critical phase in Southwestern history, from about 4000 BCE to 500 BCE, when humans first started to re-settle the desert Southwest and develop farming methods for maize. Very little has been found and little is known from this phase of Southwestern history, which is thought to be ancestral to the Mogollon culture.
     Study co-leaders Dr Jesse Ballenger and Dr Jonathan Mabry and their colleagues began investigating Cave Creek Midden in the fall of 2014, uncovering what previous excavations had either missed or dismissed - a deep layer of dark soil about 45 centimetres thick, rich with cobbles, bison bones, and a few stone artefacts. The dark soil marked the boundaries of what had been a spring-fed wetland, and has been radiocarbon dated to about 1,300 BCE.
     Shaped hand tools were also present in large numbers. What seems to be absent are the butchering and cooking tools usually associated with bison kill sites - the projectile points, choppers, knives, and pounders.
     Out of the 83 bison-bones that contained marrow, only two were found to have been broken open. It could be that at least some of the bison simply got stuck in the muck. Nonetheless, the fact that bison have been found here at all is surprising.

Edited from Western Digs (21 March 2016)