300 million-year-old ‘supershark’ fossils found in Texas

Even before the age of dinosaurs, big toothy predators were roaming Texas. 300 million years ago, during a time called the Carboniferous, the area surrounding what is now Dallas, Texas was flooded by a shallow sea. Fossils from this ancient environment were recently recovered from Jacksboro, Texas. Among these were two fossil braincases from massive extinct relatives of modern-day sharks.
Paleontology News — ScienceDaily