A bit of the Jurassic era is going on sale this week when a gallery auctions off a 150-million-year-old complete skeleton of a dinosaur. The rare fossil of the 9-foot (3-meter)-long dryosaurus could bring up to $500,000, according to the I.M. Chait Gallery. Josh Chait, who runs the gallery, said the fossil was taken from private land in Wyoming in 1993 and is being sold by Utah-based Western Paleontological Laboratories. Other fossils for sale include a 20,000-year-old wooly mammoth, measuring 7 feet (2 meters) tall and 15 feet (4.6 meters) long, and a 20-foot (6-meter)-long giant marine lizard. The dinosaur skeletons are part of what the gallery is billing as a natural history auction.