A piece of ossified dinosaur tendon from the Hell Creek Formation. It almost certainly comes from an Edmontosaurus who are by far the most common dinosaur in Hell Creek and had lots of these tendons in its tail to support its weight (althouh there is an outside chance it comes from another dinosaur such as Triceratops or Anylosaurus). The last image shows these tendons in a complete hadrosaur tail. The long tendons would have linked the muscles to the vertebrae.
Comes labelled and stored in an acrylic case with padding.