This is a 10.6" jaw section of the Cretaceous, monster fish Xiphactinus audax. It's nicely preserved with eight teeth present and still partially embedded in the rock that it was found in. There has been some repair and stabilization work to the piece.
was a huge, predatory fish that lived during the Late Cretaceous. It would have been a veracious predator, growing 15-20 feet long. When alive, the fish would have resembled a gargantuan, fanged tarpon. It appeared in the BBC's Sea Monsters and National Geographic's Sea Monsters: A Prehistoric Adventure as well as being labelled a "Prehistoric Terror" in River Monsters.
The Smoky Hill Chalk Member of the Niobrara Chalk formation is a Cretaceous conservation Lagerstätte, or fossil rich geological formation, known primarily for its exceptionally well-preserved marine reptiles. It outcrops in parts of northwest Kansas, its most famous localities for fossils, and in southeastern Nebraska. Large well-known fossils
excavated from the Smoky Hill Chalk include marine reptiles such as plesiosaurs, large bony fish such as Xiphactinus
, mosasaurs, pterosaurs, and turtles.