Scientists have found ancient nail tooth shark fossils deep inside Mammoth Cave in Kentucky, revealing new information about ...

This time period took place 359 to 299 million years ago. 3 min read The Carboniferous period, part of the late Paleozoic era, takes its name from large underground coal deposits that date to it.

Deep within Mammoth Cave, the world’s longest cave system, paleontologists have uncovered the remains of a never-before-seen ...