<P> Following the Paleozoic, the Mesozoic extended roughly 186 million years, from 251.902 to 66 million years ago when the Cenozoic Era began . This time frame is separated into three geologic periods . From oldest to youngest: </P> <Ul> <Li> Triassic (251.902 to 201.3 million years ago) </Li> <Li> Jurassic (201.3 to 145 million years ago) </Li> <Li> Cretaceous (145 to 66 million years ago) </Li> </Ul> <Li> Triassic (251.902 to 201.3 million years ago) </Li> <Li> Jurassic (201.3 to 145 million years ago) </Li>

What is the difference between cretaceous and jurassic