The Petrified Forest lies in NE Arizona, just south of the Painted Desert, and the Navajo Nation. It's the first REAL desert I came across . . . all the other "Deserts" were scrubby with grasses, wildflowers and stunted desert Junipers all around. This one is truly barren - for a lot of its area there's no evidence at all of any vegetation. The ground is a soft mudstone, and the trees have metamorphosed into Agate, so as erosion has occurred, the trees are revealed, so they look as if they've been scattered around on the landscape. Some have retained their original shape as trees; others have been broken into fragments as the ground has shifted. The contrast of the red-broown trees and the dead, grey mud is interesting.