May 7 Triceratops Fossil Found in Wyoming

John B. Hatcher, an assistant to the famous paleontologist, O. C. Marsh, professor at Yale University and Vertebrate Paleontologist for the U.S. Geological Survey, visits a fossil site at the bottom of deep canyon on a ranch in Converse (now Niobrara) County in Wyoming to see the remains of a creature that Marsh would name Triceratops. Over the next several years, Hatcher excavated the fossils which became part of the collections of the U.S. National Museum.