title: Geology: a foot in the past.
authors: Tom
authors: T
authors: Clarke
mesh_terms: D000818:Animals; D001181:Arthropods / Q000502:physiology*; D005075:Biological Evolution; D004777:Environment; D005580:Fossils; D019015:Geologic Sediments; D009792:Oceans and Seas; D009864:Ontario; D013997:Time Factors