The first bones of the Supersaurus were discovered by Delta rockhound Vivian Jones in the Uncompahgre National Forest outside Delta in 1972.
Jones contacted paleontologist James Jensen of Brigham Young University, who named the Supersaurus in 1985 and developed the Dry Mesa Quarry that has produced 4,000 bones from more than 30 kinds of dinosaurs, including a shoulder girdle from a Supersaurus.
The Supersaurus bones were located in the Morrison Formation, and the dinosaur dates back to the Jurassic era about 153 million years ago.
A typical Supersaurus reached about 110 feet in length, weighed 35 to 40 tons and stood on four stout feet to support its massive body, long neck and tail and small skull.
Recent research shows that the Supersaurus is a relative of the Apatosaurus.
Jensen also reported the discovery of an Ultrasaurus from the same quarry in 1979, but that dinosaur was later determined to be another Supersaurus.