[Wikipedia] Considered Extinct, Fossil Record: Although it was commonly known from the fossil record from across the northern hemisphere, the dawn redwood was considered extinct until the mid-twentieth century. When the genus Metasequoia was first described in 1941, it was from Mesozoic Era fossils, none of which were less than 150 million years old. While studying fossil samples of the family Cupressaceae, Dr. Shigeru Miki from Kyoto University identified a divergent leaf form. He realized he had discovered a new genus, which he named Metasequoia, meaning "like a sequoia". (link added by Mary Ann Machi)