 Increasingly, such progress in stratigraphy depended on the opinions of experts with specialized knowledge of particular types of fossils such as William Lonsdale (fossil corals), and John Lindley (fossil plants) who both played a role in the Devonian controversy and its resolution.By the early 1840s much of the geologic time scale had been developed.In 1841, John Phillips formally divided the geologic column into three major eras, the Paleozoic, Mesozoic, and Cenozoic, based on sharp breaks in the fossil record.