"A publication of the Decade of North American Geology." Title on envelope: Centennial continent-ocean transects : Tectonic section displays. Accompanies set of maps, sections and profiles with title: ...

There are seven continents on Earth, or so we learned in school. But it turns out that these designations are not as straightforward as they seem, and different scientists have different views on how ...

The Midcontinent Rift is a giant tear that formed in what is now the U.S. Midwest 1.1 billion years ago. Nicknamed North ...