66 million-year-old dinosaur ‘mummy’ skin was actually a perfect clay mask

The scaly skin of a crest over the back of the juvenile duck-billed dinosaur Edmontosaurus annectens, estimated to be about 2 years old at the time it died. Tyler Keillor/Fossil Lab

In the badlands of eastern Wyoming, the Lance Formation is a trove of prehistoric fossils. And one area in particular — a region less than 10 kilometers (6 miles) across — has provided scientists with at least half a dozen remarkably well-preserved dinosaur specimens complete with details of scaly skin, hooves and spikes.

The paleontologist Dr. Paul Sereno and his colleagues dub it “the mummy zone” in a new study that aims to explain why this particular area has given rise to so many amazing finds and define exactly what a dinosaur “mummy” is.

In the early 1900s, a fossil hunter named Charles Sternberg fou