ReBecca Hunt-Foster

The remarkably extensive and abundant Mesozoic-aged exposures on public lands around Moab have made this region well known for ichnofossils. The nearly complete record of Upper Triassic through Lower Cretaceous rocks exposed in this area is well known for its sheer abundance of tracks and traces. This three-day field trip will visit many important classic and new sites exposed in the Bureau of Land Management’s Canyon Country District. This field trip guidebook will give one an overview of the major sites we will visit, as well as a brief summary of work previously done in these areas.

A large osteoderm found in a channel sandstone in the Williams Fork Formation (“Mesaverde Group”) of northwestern Colorado represents the first reported evidence of a large neosuchian crocodyliform in the formation in northwestern Colorado. The osteoderm is of a size and pit pattern that resembles the large alligatoroid Deinosuchus but the thickness and shape of the bone suggest possible affinities with the goniopholidid or pholidosaurid crocodyliform material known from the Campanian of southern Utah; smaller, similar osteoderms from the formation may suggest that this form was relatively abundant as juveniles. Overall faunal similarities of the Williams Fork Formation are closest to the Kaiparowits Formation of southern Utah also, but few lower level taxa can be confirmed from the Williams Fork that are not also known from other areas north and south, suggesting that the Williams Fork vertebrate fauna comes from the southern end of a transition zone between possible latitudinal provinces of Laramidia.

Mygatt-Moore Quarry in the Brushy Basin Member of the Upper Jurassic Morrison Formation is one of the more important large dinosaur quarries in the formation, yielding fossils of sauropod dinosaurs including Apatosaurus, Camarasaurus, and an indeterminate diplodocine (cf. Diplodocus or Barosaurus), the theropod dinosaurs Allosaurus and Ceratosaurus, and the ornithischians Othnielosaurus and Mymoorapelta. Fossil wood and carbonized plants are known from the deposit, and carbonized dinosaur skin has also been discovered.

We report here on a new U/Pb radiometric age for the Mygatt-Moore Quarry, from a smectitic mudstone collected at the quarry horizon. We isolated zircons using an ultrasonic separation technique and standard heavy liquid and magnetic methods, analyzed single zircons using a chemical abrasion method (CA-TIMS). The age determined for this dinosaur quarry, 152.18 ±0.29 Ma, places the quarry at the boundary between the Kimmeridgian and Tithonian stages of the Late Jurassic Period. This age can now be used to place the quarry into stratigraphic position with respect to other dated horizons in the Morrison Formation and other rock units worldwide. We will also use this age along with other ages to create a radiometrically based stratigraphic framework for the Morrison Formation.

Sauropod skin was first found by S. H. Beckles in 1852 (Czerkas, 1997) in direct association with a limb bone of Pelorosaurus. Very well preserved sauropod skin has been reported recently from embryos in Argentina (Coria and Chiappe, 2007) and from adult dinosaurs in China and North America (Lingham-Soliar, 2008, and Manning et al., 2009, respectively). The first sauropod skin recognized from the Upper Jurassic Morrison Formation of the western United States was found by Barnum Brown at the Howe Quarry in Wyoming, apparently in great abundance (Bird, 1985). Since then, extensive skin preservation has been reported from the Siber excavations, again at the Howe Quarry (Czerkas, 1992; Ayer 1999; Christiansen and Tschopp, 2010). Myers and Storrs (2007) illustrated a patch of sauropod skin from the Mother’s Day Quarry in Montana, and Czerkas (1994) reported three small patches from Dinosaur National Monument. Otherwise, reports of carbonaceous skin preservation in the Morrison Formation are extremely rare. Gilmore (1925:350) noted “black carbonized matter” around the ribs of a Camarasaurus (CM 11338) from Dinosaur National Monument but was unable to identify a scale pattern in the material to confirm its identity as skin. Even including occurrences of impressions, skin is rare in the Morrison Formation, especially compared to the number of known fossil bone and track localities, which number in the hundreds. Natural impressions of skin scale patterns are preserved in sauropod footprints in the Morrison Formation, as has been noted by Lockley and Hunt (1995) and Platt and Hasiotis (2006). Tracks from Portugal and North America suggest that tubercles on sauropod feet were relatively large (Mil´an et al., 2005; Platt and Hasiotis, 2006). Probable sauropod skin impressions, preserved in mudstone but not necessarily from the feet, have recently been reported from South Korea (Kim et al., 2010; Paik et al., 2010).

Here we report two new specimens of sauropod skin and a specimen of a second, unidentified skin type, all preserved at one site in the Morrison Formation of western Colorado

Monodominant bonebeds have been well-described for centrosaurine ceratopsid dinosaurs, with over 20 sites currently known for eight out of ten taxa. Chasmosaurine bonebeds, in contrast, are currently known from 8 sites representing only six out of 14 species. Furthermore, the minimum number of individuals also tends to be greater for centrosaurine bonebeds. These differences may be attributed to collecting bias, taphonomic bias, or genuine behavioral differences between the groups.Monodominant bonebeds are often cited as evidence for herding behaviors and complex social hierarchies, but caution is necessary. For instance, factors such as a concentration of water resources during a drought may result in high population densities of otherwise nonherding animals. Thus, depositional environments of ceratopsid bonebeds are an important piece of evidence. Centrosaurine remains are more commonly found in high energy settings (e.g., paleochannel) than the low energy settings in which many chasmosaurines are preserved (e.g., overbank/floodplain). Evidence for non-stress-related, group-living behavior is found only for certain taxa, and social behavior undoubtedly varied greatly across ceratopsids.

During the summer of 2006 and the spring of 2008, Augustana College shipped fossils to three separate destinations. Remains of the holotype specimen Cryolophosaurus, a prosauropod, and capitosaur, along with plant material, were shipped to Tokyo, Japan. This fauna was the focus of an Antarctic exposition at the National Science Museum in Tokyo. Therefore, the safe packing of these vertebrate fossils for overseas transport was vital for the future study of these remains and for the success of the exhibit. Vertebrae belonging to the holotype specimen of Cryolophosaurus from the Lower Jurassic Hanson Formation of Antarctica were later sent to Research Casting International in Trenton, Ontario (Canada) in March of 2008. Casting of a new vertebral column based on specimens recently prepared since its original casting in 2002 was the goal of this shipment. Several of the twenty-one vertebrae sent have very thin and delicate post- and prezygapophyses preserved, and the safe arrival of these specimens was critical. A labyrinthodont skull from the Triassic Fremouw Formation of Antarctica was also shipped (domestically) during April of 2008 to Washington State for collaborative research purposes. This amphibian skull is extremely thin in areas and required extra attention in packing to insure no damage would occur during the shipping process. The safe packing of these vertebrate fossils for international and domestic transport was vital for the future study of these remains.

The fossils were packed in boxes constructed of ½ inch foamcore board with an interior of G-60 foam to help contour to the shapes of the individual fossils. The delicate and less robust vertebrae of Cryolophosaurus along with the labyrinthodont skull were enclosed within individual clam-shell cradles constructed of a/c foam,Ethafoam and plaster. The remaining fossils were wrapped in a protective soft sheet of Tyvek to act as an inertmoisture barrier and placed within the box, to be followed by custom cut G-60 foam supports. The boxes were then placed within the interior of custom built plywood crates for shipment. These crates were transported to their individual destinations by shipping companies.

A bone bed in the middle part of the Javelina Formation (Maastrichtian) in Texas yielded parts of about 37 identifiable ceratopsid dinosaur bones, mostly appendicular and limb girdle elements belonging to one juvenile and two adult individuals of Torosaurus cf. utahensis. The bone bed is a lag assemblage comprising large immobile parts of the skeletons accumulated in an abandoned stream channel. In general form and proportions the postcranial bones are similar to those in Pentaceratops sternbergi and are not as robust as those in Torosaurus latus or Triceratops horridus. A few cranial elements are preserved, including parts of a parietal, squamosal, maxilla, and two dentaries. The form of the parietal fragment is comparable to that of a more nearly complete specimen of Torosaurus cf. utahensis collected nearby at about the same stratigraphic level. The bone bed material provides a basis for the first skeletal reconstruction of this enigmatic horned dinosaur. Most characters used in diagnoses of T. utahensis and T. latus are inadequate. Only the raised bar along the squamosal/parietal suture, present in T. latus; and the midline epiparietal, absent in T. latus, may discriminate the two species.

Glacier National Park in northwestern Montana holds significant geological and paleontological resources. The Middle Proterozoic sedimentary rocks exposed by the Lewis Overthrust span over 2,100 m of stratigraphic thickness, representing 800 million years of deposition. The glacial carving of the mountains and valleys that began 1.6 Ma left outcrops that are strangely unaltered. While the geological resources of the park have been substantially researched, the paleontological studies have been more sporadic. Precambrian formations of the Belt Supergroup hold a record of abundant ancient life, such as stromatolites and eucaryotes. Stromatolites within the parks were first recognized by Walcott in 1906. They have subsequently been studied in detail by Fenton and Fenton in the 1930s, Rezak and Ross in the 1950s and to a great extent by Horodyski from the mid-1970s to the 1990s. Current research conducted on the eukaryote Horodyskia moniliformis, from the Precambrian Appekunny Formation, and on the cone- and branching-shaped stromatolites of the Precambrian Siyeh Formation. These works yielded a great deal of knowledge about the paleontological history of the park but many more questions exist. Future explorations lie in the morphometric attributes, macrostructures and environmental conditions of the
local stromatolites. Detailed study of the separate units within the park could also prove useful in the further search for fossils.

Fossilized fish remains are widespread throughout the continental United States. At this time 42 park units are identified to contain these remains, although this number will surely increase as further investigations are conducted. The stratigraphic record of these remains range from Silurian to Holocene ages and preserves both marine and freshwater forms. Large concentrations and varieties of these remains are found in Fossil Butte National Monument, Grand Canyon National Park, Death Valley National Park, Petrified Forest National Park, Santa
Monica Mountains National Recreation Area and Big Bend National Park. The diversity, record and availability of these fish remains in national park units emphasizes future research needs while also informing both park staff and visitors of these important resources for stewardship and interpretation of the past.

The remains of the right pes of a theropod foot were collected in the Early Cretaceous Trinity Group in Sevier County, Arkansas in 1972. These fossils are the first and only dinosaur remains recovered from the state. However, these remains have not yet been adequate described. Characterized by differentiated pedal unguals and a laterally compressed third metatarsal, the specimen appears to be closely associated with the Early Cretaceous theropods Harpymimus and Elaphrosaurus. The specimen provides for further knowledge of a poorly understood radiation of Early Cretaceous primitive coelurosaurians east of the Western Interior Seaway.

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 savage 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.

The Late Jurassic age Mygatt-Moore Quarry is located in the middle Brushy Basin Member of the Morrison Formation. Located in western Colorado, this quarry has been worked since the early 1980s, producing a large sample of fossil vertebrate material consisting mostly of dinosaurs. For this study, 796 identifiable bones were counted from the Museum of Western Colorado's collections with the goal of characterizing the vertebrate fauna from this site for the first time. The bone sample consists of 50% sauropod bones and 30% theropod. A minimum number of 21 individual dinosaurs are represented. 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. Voorhies transportation group analysis of the sauropod bones suggests that the Mygatt-Moore sample is a mixed assemblage dominated by neither transportable nor lag groups (I nor III). Numerous bones were freshly broken before burial and several contain theropod tooth marks, while some bone fragments are highly rounded. Turtle and crocodilian material is extremely rare, and fish are unknown from the main bone layer. These data are consistent with the interpretation that the MMQ represents an ephemeral, overbank deposit with only intermittent hydraulic influence.

The Mygatt-Moore Quarry is a deposit of several thousand dinosaur bones in the Brushy Basin Member of the Morrison Formation in western Colorado. The site has been worked for nearly 30 years and many specimens have been collected. This study gathered data about the quarry from many sources to investigate the origins of the deposit. The Mygatt-Moore Quarry appears to be an attritional, delayed-burial deposit of a relatively restricted diversity of dinosaurs, with few other non-dinosaurian taxa, that accumulated in a pond deposit in an overbank setting. The entire excavated quarry is currently at approximately 550 m2. More than 2300 mapped bones occur in a layer approximately 1 m thick, and more than 58% of observed bones are in the lower 33 cm of the deposit. Drill cores indicate that the extent of the deposit runs 80–100 m west and southwest and may cover at least a total of 4100 m2. Clay clasts, rare rock fragments, and abundant calcium carbonate nodules at the base of the deposit were washed in, and REE analysis indicates that the nodules may have originated from two sources. A U/Pb date, calculated from zircons identified in a mudstone sample collected from the bone layer, gave an age of 152.18 Ma +/-0.29 Ma, making the quarry approximately the same age as Reed’s Quarry 9 at Como Bluff. Plants identified from the site include abundant Equisetum and conifer wood, plus Isoetaceae, Czekanowskia, Ginkgo, ferns such as Coniopteris, and conifers such as Brachyphyllum. The gastropod Viviparus reesidei has been identified at the base of the deposit. Vertebrate fossils include several small, indeterminate reptiles, a goniopholidid crocodylomorph, and the dinosaurs Ceratosaurus, Allosaurus, Apatosaurus, Camarasaurus, Mymoorapelta, Othnielosaurus, and an indeterminate diplodocine (cf. Diplodocus or Barosaurus). The bone layer is dominated by skeletal remains of Allosaurus and Apatosaurus, with other dinosaur taxa much more rare. The MNI is 22, and the sample is mostly adults, with several juveniles and one sub-adult. Shed theropod teeth are very abundant (N = 419), and 97.6% of identifiable teeth belong to Allosaurus (only 9 have been positively attributed to Ceratosaurus). Most of the sample consists of teeth, vertebrae, ribs, and fragments; cranial and other elements are less abundant but are not unusually so – observed abundances are close to expected values based on numbers in a single skeleton. Voorhies group analysis suggests that identifiable material is semi-autochthonous and is neither winnowed nor transported in to the area. Material at the site is almost universally disarticulated. The rate of articulation ( 0.337%) is the lowest among eight major quarries of the Morrison Formation that were analyzed; only Cleveland-Lloyd was close (1.98%). Taphonomic modifications include trampling breaks, abundant corrosion, and tooth marks; degrees of weathering and abrasion were low. Bones from the site seem to have had two main sources: the better preserved, identifiable elements seem to have been from the local area and were semi-autochthonous, whereas a “background” component of small, rounded bone fragments in densities up to 100/m3 were allochthonous and probably transported in to the site some distance. Most of these small fragments are about 5 cubic centimeters in volume, with a mean of 6.78 cc and a maximum in the excavated test meter of 45+ cc. Histological samples of representative bones indicate that preservation of osteons ranges from moderate (micro-fractured) to pristine even among the allochthonous bone fragment component of the quarry, suggesting that these elements may derive from multiple sources as well. Rose diagrams plotting the azimuths of 508 long bones show no preferred orientation to the material. Preservation of abundant plant material throughout the bone layer indicates that acidic soil conditions were common at the time; preservation of at least five patches of carbonized dinosaur skin and skin impressions suggests the possibility of dyoxic conditions in the soil as well. The Cleveland-Lloyd Quarry, otherwise a close correlate of the Mygatt-Moore Quarry, demonstrates significant differences upon close inspection. Large quarries in fine-grained facies in the Morrison Formation possess a very different preservation mode and profile from those in coarser sediments, which suggests that more may be learned in the future from study of large quarries in mudstones.

The Williams Fork Formation is a late Campanian-earlyM aastrichtian unit of the Mesaverde Group, and this study focuses on the exposures found on Bureau of Land Management-administered lands in northwestern Colorado. The formation is comprised of thick sandstones, dark, often carbonaceous mudstones, and coals representing a coastal, prograding deltaic sequence bordering the Western Interior Seaway. Previously
reported vertebrates in the Williams Fork Formation include mostly terrestrial taxa such as an indeterminate tyrannosaurid, an indeterminate hadrosaur, several other ornithischians (identified from teeth), and the ceratopsian Pentaceratops; at least four
genera of small theropods have been identified by isolated teeth as well. In addition, at least 15 species of mammals have also been reported. Although a number of nondinosaurian,
non-mammalian taxa have been mentioned previously, none has received much attention in this important formation. A survey of more than a dozen localities in the upper Williams Fork Formation reveals a paleofauna that reflects the freshwater, channel and swamp setting of the formation in this area. The paleofauna includes: the ray Myledaphus, represented by teeth; the gar Lepisosteus, represented by scales, teeth, and a fin spine; the giant amioid Melvius, represented by at least one 6 cm-diameter vertebra, plus smaller individual amioids represented by teeth; the turtles Adocus, Aspideretoides, and indeterminate Macrobaenidae?, represented by shell elements; indeterminate
Crocodylia represented by teeth, osteoderms, and a vertebra; indeterminate hadrosaurids represented by a femur, metatarsal, and phalanx (from different localities); an indeterminate ceratopsian, represented by a horn core fragment; and many indeterminate bone fragments. The biota sampled during this study also included plants, represented by petrified wood, leaf fragments, and amber, and mollusks, including bivalves and both
lymnaeid and viviparid gastropods. The sample includes more than 290 specimens; of more than 170 identifiable specimens, 89.1% are freshwater aquatic or semi-aquatic species, and chondrichthyan and actinopterygian elements alone account for 47.4% of the sample. Turtles and crocodylians comprise 23.1% and 8.7% of the sample, respectively. These aquatic and semi-aquatic taxa thus likely dominate the Williams Fork Formation
paleofauna overall.

For the decade following George Callison’s paleontological survey of Colorado National Monument in western Colorado in 1977, little paleontological work had been done in this unit of the National Park Service. Foster (1998), however, listed several sauropod tracksites in the Morrison Formation of the Monument. In 2001, the Museum of Western Colorado began working with the monument to document new paleontological sites and monitor those previously found. Work by museum crews, and by Ryan King and Josh Smith, documented a number of dinosaur track sites in the canyons of the monument, both in-place and in fall blocks of Wingate Sandstone. Most of these tracks consist of Grallator specimens from about 6 to 17 cm in length (King et al., 2004), and they occur as both natural casts and impressions. At least seven of the sites occur in Ute Canyon. A second, monument-wide survey by Kelli Trujillo and others in 2004 documented more sites and relocated many of Callison’s sites. Most significant among the new finds was the tooth plate of a lungfish from the lower Morrison Formation (Imhof and Trujillo, 2005). In 2005, Fruita resident Marilyn Sokolosky showed museum crews a track site in the lower Morrison Formation that contained only the second known occurrence of turtle tracks from the Late Jurassic of North America (Lockley and Foster, 2006). Not far from this site, and at the same stratigraphic level, was a second locality with tracks of a theropod and an ornithopod, the latter assigned to Dinehichnus (Lockley and Foster, 2006). Part of the slab of turtle tracks was collected in September 2010. Around the same time, a small theropod or ornithopod track was found in the lower Morrison near Artists Point by Jim Robertson, a monument maintenance employee. In this same area a new type of track, possibly belonging to small reptiles, were found in the lower Morrison by John Foster and ReBecca Hunt-Foster.

The partnership between Colorado National Monument and the Museum of Western Colorado strengthened this year with the collaboration for the first ever National Fossil Day. On October 12, 2010, Colorado National Monument and the Museum of Western Colorado partnered to provide a paleontology focused field trip to over 230 fourth grade students in honor of the first ever National Fossil Day. National Fossil Day, hosted by the National Park Service and the American Geological Institute, is a celebration organized to promote public awareness and stewardship of fossils, as well as to foster a greater appreciation of their scientific and educational value. During this National Fossil Day celebration, students visited both the museum and the monument. At the museum the students learned about how fossils form, geologic time and the geology of our area, and about fossils we find locally. At the monument the students took a ranger-guided hike in the relevant geologic strata. The content of the field trip not only highlighted local fossil discoveries but also aligned with Colorado state science standards. Junior Paleontologist activity books were distributed to the three local, participating schools prior to the field trip date. Students completed educational fossil activities and were awarded their Junior Paleontologist badges during the field trip. The fourth graders were the first public to witness the “unveiling” of newly recovered fossilized turtle tracks that were on display at the monument and later moved to the museum. Colorado National Monument also hosted a public fossil “unveiling” on October 13, 2010, highlighting the recent discoveries, new exhibits, and honoring George Callison, John Foster and Bill Hood for their contributions to paleontological and geological research in the monument.

The partnership between Colorado National Monument and the Museum of Western Colorado has grown over the years, resulting in numerous educational opportunities, cooperative exhibits, and increased scientific research. This great working relationship benefits not only the residents of western Colorado, but all visitors to both venues.

With its description in the 1990s, Mymoorapelta maysi became the first well-documented Jurassic ankylosaur. This was soon followed by the description of Gargoyleosaurus. Although both are from the Morrison Formation and the preservation of Mymoorapelta is better, the nearly complete skull of Gargoyleosaurus made it favored with taxonomists. However, continued excavations at the type location, the Mygatt-Moore Quarry in westernmost Colorado, have resulted in the recovery of nearly every skeletal element of Mymoorapelta, including parts of the skull, making it the most complete Jurassic ankylosaur. Skull elements include jugal, postorbital, quadrate, braincase, and teeth and compare well with Gargoyleosaurus, whose jugals, quadrates, and braincase were damaged on discovery. Of the major postcranial skeleton only the pubis and femur are not represented, which are the only elements known from the hind-quarters of Gargoyleosaurus. All elements of the armor are well-represented including significant portions of both cervical rings (nodosaurids have three cervical rings). Clearly, Mymoorapelta and Gargoyleosaurus are very similar in nearly every morphological feature observed on the shared preserved skeletal elements. Mymoorapelta preserves a mosaic of characters relative to more derived ankylosaurs that may provide important information as to what are the primitive character states. The ischium is bent as in polacanthines and nodosaurids indicating to us that the straight ischium of ankylosaurids is actually derived. The scapular spine forms a vertical ridge opposite the glenoid in Mymoorapelta as in ankylosaurids and the only other Morrison ankylosaur scapula from the Dry Mesa Quarry in western Colorado. Mymoorapelta has short limbs with even shorter distal limb elements as in ankylosaurids and polacanthines. This new analysis indicates that Mymoorapelta and Gargoyleosaurus are outside of both Ankylosauridae and Nodosauridae and that the Polacanthinae should be restricted to Polacanthus, Hylaeosaurus, Gastonia, and Hoplitosaurus.

In July of 1941, J. W. Stovall of the University of Oklahoma, with graduate student Don Savage and undergraduate Wann Langston, Jr., traveled to the San Juan Basin of New Mexico to collect fossils for the University of Oklahoma Museum. While on this trip they discovered the remains of the largest and most complete specimen of Pentaceratops sternbergi (OMNH 10165). Unfortunately, the locality of this important find has been lost. Dr. Wann Langston, Jr., has documented the find to the best of his recollection, but the site has never been relocated. It has been suggested by others that the locality may not be in the documented region, but rather north of this area. In April of 2009 Nick Longrich and ReBecca Hunt-Foster attempted to relocate the 1941 the University of Oklahoma Pentaceratops quarry, following the notes of Wann Langston, Jr. (1989). While the location of the historic quarry was not located during the course of this particular search, several other previous quarries were identified. Locating the historic 1941 Pentaceratops quarry will help to better constrain the geologic age of this particular specimen, which is located in either the Fruitland Formation or Kirtland Shale.

An otherwise essentially complete Tricrepicephalus texanus found in the Weeks Formation (Cambrian, global Series 3, Guzhangian) at North Canyon, Utah, is missing the distal half of the left pygidial spine, with the broken surface slightly rounded off and more rugose than the smoother, intact part of the spine. The right spine is intact and complete. The full specimen (SUSA 3163) is 53 mm long, and most other elements of the skeleton appear intact (except the lateral part of the left librigena, including the genal spine, which is missing). The right pygidial spine is 11 mm long, but the broken left spine preserves only slightly over 5 mm of the basal portion. There is no extra mineralization or deformation indicative of a pathology or teratological origin for the shortened spine, and the completeness of the rest of the skeleton suggests that the short spine is not a taphonomic modification. The blunt, rounded nature of the shortened spine, and its slightly rugose texture, suggest that it was injured and healed, perhaps as a result of failed predation by an unknown predator. The broken spine differs significantly from that in a previously described Tricrepicephalus (also a left) from another formation in that the previous specimen lost the entire spine at the base (up against the pygidium), and it was the spine-pygidium junction that healed in that specimen. In being short, blunt, and possibly regenerated, the pygidial spine of SUSA 3163 is similar to a broken and healed right genal spine in a specimen of Cedaria minor from the Weeks Formation (KUMIP 259299).
Predation injuries are commonly recognized on pleural lobes (particularly posteriorly), pygidia, and cephala of trilobites; such injuries are expected on presumably defensive spines of the mineralized exoskeleton, but distinguishing these injured spines from those resulting from other causes can be difficult. Interestingly, injuries and other damage to the spines of olenelloid trilobites seem to be comparatively rare. The documentation of broken and healed, and otherwise pathological, pygidial spines in several specimens of Tricrepicephalus indicates both the defensive nature of the spines and the ability of the animals to survive what appears to be relatively frequent attempted predation, likely by other arthropods.

The Early Jurassic Navajo Sandstone is a vast eolian deposit that represents the largest erg to have existed on Earth. Exposed throughout southern Utah, the Navajo Sandstone contains localized, water-lain interdune deposits consisting of impermeable, fine-grained sediments. Through both trace and body fossil evidence, these interdunal “lakes" are known to have supported a relatively diverse biota, and are increasingly the subject of paleontological studies. Additionally, these impermeable interdune deposits are studied by geomorphologists for their role in groundwater sapping and the creation of alcoves and box canyons within the Navajo Sandstone.
The ruins of a Pueblo III period structure with some Basketmaker II/III components is located in a small, multi-component cliff dwelling in a Navajo Sandstone alcove located on Bureau of Land Management land in San Juan County, Utah. These ruins indicate the structure was constructed almost entirely of rectangular blocks of creme-colored eolian Navajo Sandstone, except for a single slab of flat, pinkish, fluvial sandstone which serves as the lintel over the struture entrance; the lintel likely originated in either the Late Triassic Chinle Formation or the Early Jurassic Kayenta Formation (although other formations remain a possibility), which are both fluvial and are both located nearby (within walking distance). The lentil is also unique in that it bears a fossilized dinosaur track, facing down into the constructed passageway. The track is preserved in convex hyporelief and is identified as Grallator isp., made by a relatively small, three-toed, theropod dinosaur. This track type is well-documented in southern Utah where the Navajo Sandstone, Chinle Formation, and Kayenta Formation are exposed.

As the Chinle and Kayenta Formations are not immediately adjacent to this cliff-dwelling, and the Navajo Sandstone does not contain fluvial beds of this nature nearby, the slab with the fossilized track appears to have been transported here from another location and then deliberately placed as the lintel in this structure by the builders. The practice of incorporating vertebrate ichnofossils into cliff-dwelling structures, Pueblo III or otherwise, in the American southwest is heretofore unknown and this discovery is the first such documented occurrence.

n 2009, the Paleontological Resources Preservation Act was enacted, instructing the Secretary to manage and protect paleontological resources on Federal Land using scientific principles and expertise, and to develop plans to increase public awareness about the significance of paleontological resources. Many rural communities throughout the country remain underserved due to lack of resources to support actual visits to fossil sites. In response, short educational videos, lesson plans, educational trunks, tours, and onsite activities (that teach site stewardship and the scientific process) have been developed for the K-college age audience. These are used in the classroom as well as to support exploratory, place-based learning experiences (i.e. outside laboratories) at Bureau of Land Management (BLM) fossil sites in Wyoming and Utah.
The Red Gulch Dinosaur Tracksite (RGDT) in Wyoming, Moccasin Mountain Tracksite (MMT) and Mill Canyon Dinosaur Tracksite (MCDT) in Utah, are some of the best examples of sites that have been studied and developed with education of the general public in mind. Once these sites were thoroughly documented, they were developed for more formal site visitation (e.g., creation of boardwalks, trails, interpretive signs, shade structures, and other amenities). BLM partnered with “Hands on the Land,” researchers, and friends groups to develop educational activities and provide them to teachers. The exercises developed are designed to promote the importance of stewardship toward the natural world by presenting the benefits of preservation, for current and future generations to have a better scientific understanding of past and present environments and ecosystems. Scientific observation and interpretation techniques are illustrated and students can do their own discovery, measuring, and mapping of tracks to come up with their stories of the tracksites. The physical lesson plans and activities that have been developed are for use both onsite and in the classroom, while the videos can be viewed both at these public fossil sites and online. New activities and information continue to be developed, as new information becomes available. Current projects include the development of additional videos and Junior Rangers books, which can be used by teachers locally, as well as nationwide.

A partial skull collected in the Mancos Shale northwest of Grand Junction, Mesa County, Colorado, represents the first specimen of the ichthyodectid fish Xiphactinus audax reported from the formation in western Colorado. The Museum of Western Colorado specimen is from the Smoky Hill Member of the Mancos and is likely Coniacian or Santonian in age. The specimen is well preserved and consists of both premaxillae, the left maxilla, a fragment of the right maxilla, both dentaries, a ceratohyal, another indeterminate skull bone, two vertebrae, several fragments of pectoral fin spines, numerous rib and vertebral spine fragments, and nearly 400 scales. The only other Xiphactinus specimens from the Mancos Shale are a partial skeleton from near Snowmass, Colorado, at the Denver Museum of Nature and Science and very fragmentary field evidence from near Green River, Utah. All three occurrences of Xiphactinus in the Mancos Shale in Colorado and Utah (plus recent reports from the Tropic Shale of Utah) are unreported in previous summaries of the genus but push the distribution of Xiphactinus farther west in its southern distribution.