The North American craton actually dips near the Rockies rather than forming a sharp vertical step as previously believed.

An analysis of landscape features and of river deposits preserved in caves point to an event 2.1 million years ago that triggered the formation of Hells Canyon. The authors determined the age of river ...

An ancient slab of Earth's crust buried deep beneath the Midwest is sucking huge swatches of present-day's North American crust down into the mantle, researchers say. The slab's pull has created giant ...

A group of fossils of elasmosaurs—some of the most famous in North America—have just been formally identified as belonging to a "very odd" new genus of the sea monster, unlike any previously known.