McInnis Canyons Mygatt-Moore Quarry Gives Up Fossil Clues

John and I have been continuing our research out at the Mygatt-Moore Quarry in western Colorado, and recently had a paper on one of our findings published in the Journal of Vertebrate Paleontology in May.

Foster, John R. and Hunt-Foster, Rebecca K.(2011) 'New occurrences of dinosaur skin of two types (Sauropoda? and Dinosauria indet.) from the Late Jurassic of North America (Mygatt-Moore Quarry, Morrison Formation)', Journal of Vertebrate Paleontology, 31: 3, 717 — 721 DOI: 10.1080/02724634.2011.55741

We work each summer at this quarry under a paleontological permit from the Bureau of Land Management, which is located in the McInnis Canyons National Conservation Area (NCA), near the Colorado/Utah state line. “The national significance of the area's paleontological resources is one of the many reasons this special place was designated as a National Conservation Area,” said Katie Stevens, NCA Manager for the BLM’s Grand Junction Field Office. “With experts like John and ReBecca working in these quarries, we can recover and share this exciting and important scientific information with the public.” John is currently working under a scientific grant from the BLM to better understand the extent of the quarry and the conditions that made it such an ideal location for preserving fossils [details].

The first specimen was located by Jim Kirkland and his expedition to the quarry in 1993 (MWC 1903). A expedition member, Dan Libecap, discovered the second specimen (MWC 5537) in 2003. Two of our museum volunteers, Kay Fredette and Ray Bley, uncovered the most recent specimen (MWC 6718) in 2008.

Two of the three specimens (MWC 6718 & 5537) are possibly from sauropods, and we attributed the third specimen to Dinosauria indeterminate (MWC 1993). The two possible sauropod specimens represent the first occurrence in the Morrison Formation of preserved sauropod skin associated with abundant nearby specimens of Apatosaurus. They also show how similar the general structure of skin patterns within known Morrison diplodocids are.

Specimen MWC 6718 - carbonized sauropod? skin impression from the Mygatt-Moore Quarry. Morrison Formation (Upper Jurassic) of Mesa County, Colorado. scale bar =5 cm

These discoveries were unique because the soft tissue associated with the skin was preserved as carbonaceous layers rather than as trace fossil impressions, yielding better information about skin pattern, scale size and scale shape. This discovery is is the sixth occurrence recovered from the Morrison Formation.

If you would like a PDF of this paper please contact me here or by email and I would be happy to share one with you. We plan for this paper to be the first of many that will be published over the next few years. Below is a complete bibliography of research from Mygatt-Moore Quarry that has been done to date (PDF's of select papers are also available):

Foster, John R. and Hunt-Foster, Rebecca K. (2011). New occurrences of dinosaur skin of two types (Sauropoda? and Dinosauria indet.) from the Late Jurassic of North America (Mygatt-Moore Quarry, Morrison Formation) Journal of Vertebrate Paleontology, 31 (3), 717-721 : 10.1080/02724634.2011.55741

Foster, John R. 2007. Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indian University Press, 416 pages.

Foster, John R; Hunt, ReBecca K; King, Lorin. 2007. Taphonomy of the Mygatt-Moore quarry, a large dinosaur bonebed in the Upper Jurassic Morrison Formation of western Colorado. Geological Society of America, 2007 annual meeting, Abstracts with Programs - Geological Society of America, vol. 39, no. 6, pp.400

King, Lorin R; Foster, John. 2006. Under the feet of giants; an investigation of the small vertebrates at the Mygatt-Moore Quarry, Morrison Formation, western Colorado. Sixty-sixth annual meeting, Society of Vertebrate Paleontology; abstracts of papers. Journal of Vertebrate Paleontology, vol.26, no.3, Suppl., pp.85

King, Lorin R; Foster, John R; Scheetz, Rodney D. 2006. New pterosaur specimens from the Morrison Formation and a summary of the Late Jurassic pterosaur record of the Rocky Mountain region. In (editors - Foster, John R; Lucas, Spencer G) Paleontology and geology of the Upper Jurassic Morrison Formation. Bulletin - New Mexico Museum of Natural History and Science, vol.36, pp.109-113

Foster, John. 2005. Evidence of size-classes and scavenging in the theropod Allosaurus fragilis at the Mygatt-Moore Quarry (Late Jurassic), Rabbit Valley, Colorado. Sixty-fifth annual meeting, Society of Vertebrate Paleontology; abstracts of papers. Journal of Vertebrate Paleontology, vol.25, no.3, Suppl., pp.59

King, Lorin; Foster, John; Scheetz, Rodney. 2005. Mesadactylus and other new pterosaur specimens from the Morrison Formation (Upper Jurassic) of western Colorado. Sixty-fifth annual meeting, Society of Vertebrate Paleontology; abstracts of papers. Journal of Vertebrate Paleontology, vol.25, no.3, Suppl., pp.78

Kirkland, James I. 1998. Morrison fishes. Modern Geology 22: 503-533

Tidwell, W.D., Britt, B.B., and Ash, S.R. 1998, Preliminary floral analysis of the Mygatt-Moore Quarry in the Jurassic Morrison Formation, west-central Colorado: Modern Geology 22: 341-378

Chin, K. and Kirkland, J.I. 1998. Probable herbivore coprolites from the Upper Jurassic Mygatt-Moore Quarry, Western Colorado. Modern Geology 23: 249-275.

Kirkland, J. and K. Carpenter. 1994. North America's first pre-Cretaceous ankylosaur (Dinosauria) from the Upper Jurassic Morrison Formation of Western Colorado. Brigham Young University Geology Studies, 40:25-42.

Kirkland, James I; Armstrong, Harley J. 1992. Taphonomy of the Mygatt-Moore Quarry, middle Brushy Basin Member, Morrison Formation (Upper Jurassic), western Colorado. Society of Vertebrate Paleontology, fifty-second annual meeting. Journal of Vertebrate Paleontology, vol. 12, no. 3, Suppl., pp.37A

Mygatt, Peter. 1991. The Mygatt-Moore Quarry, Rabbit Valley, Mesa County, Colorado. Pages 57-58 in (editor - Averett, Walter R.) Guidebook for dinosaur quarries and tracksite tour, western Colorado and eastern Utah. Grand Junction Geol. Soc., Grand Junction, CO