Richard Swann Lull studied zoology at Rutgers College and paleontology at Columbia University. He was an Assistant Professor of Zoology at what would become the University of Massachusetts, Amherst. While there, he became interested in the collection of fossil footprints at the nearby campus of Amherst College and decided to become a paleontologist.
He was part of an excavation in Wyoming with the American Museum of Natural History, where they unearthed the skeleton of a brontosaurus, and worked with AMNH again in Montana. He studied under Henry Fairfield Osborn, earning his Ph.D. from Columbia University in 1903. After working briefly at Amherst College, Lull moved over to Yale, where he remained for fully 50 years. He taught vertebrate paleontology and became Curator of Vertebrate Paleontology and eventually director at the Yale Peabody Museum.
In 1904, Lull wrote the first new study of the fossil footprints that had been done since Edward Hitchcock's 1858 Ichnology of New England and its supplement in 1865. His Triassic Life of the Connecticut Valley, published in 1915, was a detailed examination of the geology, flora, and fauna of the region, with nearly half its 265 pages devoted to fossil footprints. Lull aimed to bring the Triassic vividly to life, describing the environment and evidence of organic life. He used photographs for illustration and, in the tradition of 19th-century paleontologists, had help from his wife in preparing illustrations.