Cooperative Management of Paleontological Resources on Federal Lands in Mesa County, Colorado

The abstract John and I wrote for the 8CFR was trimmed for some reason, so here is our intended abstract in its original entirety:

Cooperative Management of Paleontological Resources on Federal Lands in Mesa County, Colorado

HUNT-FOSTER, ReBecca K., and FOSTER, John R., Museum of Western Colorado, Dinosaur Journey, 550 Jurassic Ct., Fruita, Colorado 81521

The Museum of Western Colorado has long had a history of working in cooperation with the local federal agencies (particularly the Bureau of Land Management) to help manage and preserve the unique and important paleontological finds of Mesa County, Colorado. Some of the most important areas on BLM land (most within McInnis Canyons National Conservation Area) have been designated as Museum/BLM cooperative management Research Natural Areas, set aside for their paleontological resources.

Museum projects with the Grand Junction Field Office of the Bureau of Land Management date back to at least 1976 with the excavation of the type specimen of Ceratosaurus magnicornis from the Fruita Paleontological Area (FPA). With the 1981 discovery of the Mygatt-Moore Quarry (MMQ) in Rabbit Valley, the museum began a 25 year working relationship with the local BLM field office to study this locality in the Morrison Formation, one of the largest dinosaur sites in the unit. Further work in the BLM lands of Rabbit Valley has included the excavation of the Averett Camptosaurus in 1982 and the Bollan Stegosaurus in 1986. Other activities in Rabbit Valley have included the construction of the Trail Through Time. This mile-and-a-half loop trail takes visitors through an interpreted hike along Jurassic-age river channels. An interpretive kiosk at the trail head describes the flora and fauna of the Morrison Formation as well as activities that take place at the Mygatt-Moore Quarry. Explanations of fossilized bones seen in situ are given on interpretive panels along the trail.

The Museum also worked with the local BLM field office to build a trail though the Split Rock area of Rabbit Valley. This developed trail leads the public though a Jurassic-age river channel that has produced a high abundance of dinosaur material, including a partial skeleton of the small ornithopod Othnielosaurus. In 2002-2003, with assistance from the BLM, the museum worked to salvage an Allosaurus skeleton that was being vandalized along the Split Rock trail. In 2004-2005 an articulated Apatosaurus was removed from maroon mudstone in the Twin Juniper Quarry in Rabbit Valley.

The Museum has worked with Colorado National Monument resource managers to inventory Jurassic tracksites in the Wingate Sandstone in the canyons of the monument (mostly Grallator trackways), and to collect, preserve and study only the second known set of turtle tracks from the Morrison Formation.

Elmer Riggs of the Field Columbian Museum excavated an Apatosaurus in Fruita, Colorado, at Dinosaur Hill, in 1901. This site is important because the specimen led to Riggs’s recognition that Apatosaurus and Brontosaurus represented the same animal. A trail was installed at this site in 2003 to interpret the unique history and paleontological resources of the area. A trail at the nearby FPA was installed in 2001 to interpret the globally significant mammal fauna of the Morrison Formation found there. The trails at Dinosaur Hill and at the FPA are cooperative efforts managed by the Bureau of Land Management, the Museum of Western Colorado, and the City of Fruita.

The Late Jurassic-age Mygatt-Moore Quarry is located in the middle Brushy Basin Member of the Morrison Formation. Excavations have taken place every year since 1984 (25 seasons) at the Mygatt-Moore Quarry. On this BLM-managed land the Museum leads public fossils digs for four months a year, with 250-350 public diggers per year participating under the supervision of staff paleontologists. This hands-on opportunity gives the museum the opportunity to convey important scientific information, while also education the public on the importance of stewardship and fossil resource protection on federal lands. Over 800+ cataloged specimens from seven species of dinosaur, including the type specimen of the first Jurassic ankylosaur Mymoorapelta, have been recovered from this bonebed. The most abundant taxon at the quarry is the theropod Allosaurus (29%), which is represented by 233 skeletal elements indicating a minimum of 6 individuals (5 adults, 1 juvenile); in addition, more than 190 mostly shed teeth of Allosaurus have been recovered from the site. The sauropod Apatosaurus is next most abundant (20%) with 160 elements representing 5 individuals (3 adults, 1 sub-adult, 1 juvenile). Approximately 19% of the sample consists of bones of the ankylosaur Mymoorapelta, mostly osteoderms and lateral spines (2 individuals). The three most abundant sauropods in the Morrison Formation (Camarasaurus, Apatosaurus, and Diplodocus) also are preserved at the Mygatt-Moore Quarry, but unlike within the formation as a whole, at the MMQ Apatosaurus accounts for 85% of the sauropod bones at the site; in the formation overall, Camarasaurus is the most abundant sauropod. Also preserved at the site are the carnivorous dinosaur Ceratosaurus (6 teeth) and the small ornithopod dinosaur Othnielosaurus (one jaw fragment), the latter first identified during the 2008 season. Non-dinosaurian taxa preserved at the site are very rare but include a turtle, a crocodilian, and a probable pterosaur.

Above the main bone layer at MMQ is a shallow lake deposit, which preserves some of the only articulated fish skeletons in the Morrison Formation, including “Hulettia” hawesi and the type and referred specimens of Morrolepis schaefferi. Also found in this unit have been the fish cf. Leptolepis and an as yet unnamed crayfish.

Museum of Western Colorado and the Grand Junction Field Office of the BLM are investigating the possible installation of a permanent protective building over the Mygatt-Moore Quarry. Given the abundance of large, well preserved dinosaur bones at this site, the building could serve as a permanent and educational exhibit that would help to interpret the quarry in the long term, while also providing year-round access and a secured, on-going excavation area.


© ReBecca K. Hunt-Foster and John R. Foster