Abstract
Yellowstone National Park surpasses all other sites in the United States forits petrified wood, for here is found large amounts of it, in an exquisite stateof preservation. In and around Yellowstone Park, erosion has exposed in crosssections an incredible sequence of rather flat-lying rock layers, eachcontaining numerous petrified trees. Many of these trees are upright, in growthpositions. The question remains, are they in growth location?