About 65 million years ago, just after the dinosaurs died out, this corner of North Dakota was a flat, swampy delta under sequoia, bald cypress and magnolia, and sediment washing down from the young Rockies buried the trees fast enough to turn them to stone. Theodore Roosevelt National Park now holds the third-highest concentration of petrified wood in the United States. The trail climbs out of the badlands onto open prairie and splits, and each branch drops into a valley of stone stumps about a mile and a half from the trailhead; the whole loop is 10.4 miles. The trailhead is about 50 minutes from Medora on dirt and gravel: use the approved route from I-94 exit 10 toward Camels Hump Lake and follow the marked posts past private ranches. There is little or no shade, so carry a liter of water per person per hour in summer. No pets, and every stump and chip stays where it lies.
Petrified stumps of sequoia, bald cypress and magnolia · Paleocene, ~65 mya
This ground is protected. Photograph it, record it, leave it where it lies. On US federal land the Paleontological Resources Preservation Act 2009 makes collecting vertebrate fossils an offence, and penalties are real.
Other places on the map within a couple of hours.
