Yellowstone National Park
Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .
Travertine
In the U.S., the most well-known place for travertine formation is Yellowstone National Park, where the geothermal areas are rich in travertine deposits. Wyoming also has travertines in Hot Springs State Park in Thermopolis. Oklahoma has two parks dedicated to this natural wonder. Turner Falls, the tallest waterfall in Oklahoma, is a cascade of spring water flowing over a travertine cave. Honey Creek feeds this waterfall and creates miles of travertine shelves both up and downstream. Many small waterfalls upstream in the dense woods repeat the travertine-formation effect. The city of Davis now owns thousands of acres of this land and has made it a tourist attraction. Another travertine resource is in Sulphur, Oklahoma, east of Turner Falls. Travertine Creek flows through a spring-water nature preserve within the boundaries of the Chickasaw National Recreation Area.