American paleontologist, paleopedology.
Gregory John Retallack (born 8 November 1951) is an Australian paleontologist, geologist, and author who specializes in paleopedology, the study of fossil soils. He is a professor emeritus at University of Oregon and his research is primarily concerned with the fossil record of soils though Earth history. His research has included investigations into climate change, the extinction of dinosaurs, the origins of upright walking humans. Retallack has controversially claimed that Ediacaran-era fossils represent terrestrial lichens as opposed to the consensus view that they present marine organisms