Paleo Slide Set: Packrat Middens: Vegetation & Climate Variability in the Southwestern United States
Lake Powell [1200 m] and Navajo Mountain [3166 m]

The Four Corners area (Arizona, Colorado, New Mexico, Utah), is another region of extensive 
packrat midden research. Typical of this region are extensive outcrops of the same geologic 
formation spanning various elevations. One of these formations, the Navajo Sandstone, was once 
giant sand dunes formed during the Jurassic period. The Navajo Sandstone is notorious for its 
large caves and rock shelters, harboring prehistoric cliffhouses such as Betatakin and Kiet Siel. 
Occasionally, individual caves can also harbor entire midden sequences. In such cases, the middens 
represent a floral, compositional census every few thousand years of an area no bigger than a house plot. 

Photo Credits:
Julio Betancourt 
U. S. Geological Survey