One of the leading and most influential paleoartists of the 20th century. He painted the famous "The Age of Reptiles" mural that decorates the Yale Peabody Museum's Great Hall. The 4.9 m × 34 m painting, which portrays ancient fauna beginning from when vertebrates first appeared on land all the way though the age of the dinosaurs, took three years to complete, and was unveiled in 1947. He started working on the project in his 20s, still a student.