The geologic time scale is divided into eons ... such as the transition from Jurassic to Cretaceous 145.5 million years ago. The largest extinction events define a change in era. The end of the ...

Known today as the “Black Belt,” the southeastern United States was once covered by an ancient sea—one that continues to shape modern history.

It lasted a long time, nearly 80 million years, making it the longest geological ... covered in thick, scale-like leaves with sharp edges. The group this plant belongs to was at its most diverse ...

On ten thousand to million years time ... geological climate archives from the South Atlantic and the Northwest Pacific. These key records span the last million years of the Cretaceous and are ...