Paleontologists have discovered fossils of Heleocola piceanus, a swamp-dwelling mammal that lived around 75 million years ago ...

Shallow seas formed, dividing some continents. In the Late Cretaceous, for example, the Western Interior Seaway split North America into two landmasses. At its largest this sea was more than 3,000 ...

The animal lived about 70 million to 75 million years ago in a part of the state that would likely have been a swampy environment.

Xiphactinus trolled an ancient ocean called the Western Interior Seaway, which covered much of central North America during the Cretaceous. Though long extinct, if alive today the bony fish would ...

Eberle said that finding mammal fossils from the Cretaceous period doesn't happen ... to have been very close to the coast of the Western Interior Seaway." She said the area of Colorado where ...

For most of the Cretaceous, Canada’s prairie provinces were sitting deep underwater. A giant inland sea cut right across North America. Known as the Western Interior Seaway, it ran north to ...

A map shows the “western interior seaway” that separated Appalachia and the western U.S. Map of the Western Interior Seaway, which ran through Colorado and separated Appalachia from the ...