This “Mummified” Hadrosaurid Dinosaur Vertebrae & Tail Section (estimate: $100,000 ), is a gargantuan relic that stretches more than 20 feet (6 meters) in length. Found in 1999 in Harding County, South Dakota — informally known as the “T-Rex Capital of the World” — this spectacular fossil can be traced back to the Late Cretaceous period some 100-66 million years ago. This massive vertebral and tail section comes from a plant-eating Hadrosaur. Two things make this fossil truly remarkable: the pre