An analysis of a series of thermal features spanning nearly 7,000 years of prehistory reveals the transition
   to a reliance of yucca crowns as a staple resource along the periphery of the agricultural southwest and 
   southern Great Plains.  A series of five types of thermal features were identified from a sample of over 100
   preserved fire hearths analyzed from a single region in the Mescalero Sands documenting the transition to a
   regional resource exploitation strategy reliant on the exploitation of yucca crowns.  The sample set documents
   the construction and use of thermal features in the region as early as the Early Archaic nearly 7,500 B.P. with
   a regional hiatus of the region by 700 B.P.  The analyzed fire hearths reveal the initial use or exploitation of
   yucca as early as 4820 B.P. with the use of Feature Type 3.


• Type 2 (2770 to 2180 B.P.) Middle Archaic