^James Gunnerson reports dates from 7,500 BCE to 8,890 BCE, depending upon the site and archaeologist, which would be in roughly the same, but a longer, time period.[1]
Citations
^ abGunnerson, James H. (1987). Archaeology of the High Plains. Denver: United States Forest Service. p. 16.
^ abCassells, E. Steve. (1997). The Archeology of Colorado, Revised Edition. Boulder, Colorado: Johnson Books. p. 79. ISBN1-55566-193-9.