 He continued to work on other projects, such as his "Early History of Hartford".Perhaps Zallinger's most well-known piece of art, The Age of Reptiles is a 110 feet (33.5 meters) wide by 16 feet (4.9 meters) tall mural, occupying the full length of the east wall of the Yale Peabody Museum’s Great Hall.It was painted from 1943 to 1947, with the help of a 6-month crash course in animal and plant life of the distant past and comparative anatomy with Yale's professors.