Very NICE ! That last one one is agatized (petrified ) wood. Here's a cool place to visit "One of the best places in North Dakota to find an ancient frozen forest is in the South Unit of Theodore Roosevelt National Park, located off Interstate 94 near Medora, about 130 miles west of Bismarck, ND. The petrified trees belong to many species but the largest stumps (up to 12 feet or 3.65m in diameter) belong to the genus Metasequoia – the Dawn Redwood. Those who happen to be in Bismarck can check out a 120-foot (36.5 meter) long, 6-ft (1.82m) wide petrified Metasequoia log that’s been installed on the grounds of the state capital building."