In 1960, lack of knowledge about former plant distributions in North American deserts was reversed by the discovery of plant-rich deposits or middens in caves and rock shelters in the arid
interior of North America. These so-called middens, an amalgamation of plant and animal remains encased in crystallized packrat (Neotoma spp.) urine, were noted by military and scientific expeditions across the West as early as 1849. But, it was not
until 1960 that paleoecologists fully recognized their potential for reconstructing past environmental change.
Click on above image to enlarge.
Download a zip file
of a full resolution TIF image