Thor Arthur Hansen
Contributor
LOCATION: Bellingham, WA, United States
Professor of invertebrate paleontology, paleoecology, and evolution, Western Washington University, U.S.
Primary Contributions (1)
Cretaceous Period, in geologic time, the last of the three periods of the Mesozoic Era. The Cretaceous began 145.0 million years ago and ended 66 million years ago; it followed the Jurassic Period and was succeeded by the Paleogene Period (the first of the two periods into which the Tertiary Period…
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