The Hell Creek Formation dates back to the Late Cretaceous approximately 66-68 million years in age. It represent the coastline of an ancient sea that spanned across the middle of North American during much of the Mesozoic Era. That is why dinosaur remains are so common in the American West, those areas were the ancient floodplains of a seaway that no longer exists.Dinosaur like the famous Tyrannosaurus Rex, Triceratops and Pachycephalosaurus were part of this amazing ecosystem. Other dinosaur such as Edmontosaurus, Thescelosaurus, Struthiomimus and Oviraptorids existed here as well. And of course there were the Dromaeosaurs Raptors that inhabited this area and preyed upon these species such as Acheropraptor and Dakotaraptor. The item "Serrated Tyrannosaur Premaxillary Tooth Dinosaur Fossil Hell Creek MT T Rex" is in sale since Friday, October 8, 2021. This item is in the category "Collectibles\Rocks, Fossils & Minerals\Fossils\Vertebrates\Amphibian, Reptile & Dinosaur". The seller is "hellcreekdinosaurs" and is located in Spring, Texas. This item can be shipped worldwide.