États-Unis

Gargoyleosaurus, North American Museum of Ancient Life.

Holotype of the polycotylid[1] plesiosaur Edgarosaurus muddi DRUCKENMILLER, 2002, (MOR 751) comprising the skull, the neck, and the left front flipper, on display in the Museum of the Rockies in Bozeman, Montana. The specimen was collected in Edgar, Carbon County, Montana, from the Shell Creek member of the Thermopolis Shale Formation, Upper Albian, uppermost Lower Cretaceous.[2]

Life restoration of Harpactognathus gentryii, a pterosaur from Jurassic USA

Taken at the National Geographic Museum Spinosaurus Exhibit. Photo by www.ieonexus.com

Fossil specimen in the Natural History Museum of Utah, Salt Lake City, Utah, USA. Photography was permitted in the museum without restriction.

Menefeeceratops is a genus of ceratopsid dinosaur from the Menefee Formation in the United States. It is is believed to have been approximately 4 m long, and had two large horns above the eyes like other ceratopsians. Menefeeceratops was one of the earliest and most basal known members of the ceratopsids, and the oldest known centrosaurine. Its age and location was instrumental in helping to understand the evolution and diversification of the centrosaurine dinosaurs.

Photograph of the holotype skull of Titanoceratops ouranos, from the late Campanian aged Kirtland/Fruitland beds of New Mexico, USA. Photograph by Nick Longrich

Ceratopsipes goldenensis Lockley & Hunt, 1995 - ceratopsian dinosaur trackway in the Cretaceous of Colorado, USA. Ceratopsians are the "horned dinosaurs". They were large, quadrupedal, herbivorous dinosaurs having a beaked skull and a frill - an extension of bone behind the skull that partially covered the neck. Ceratopsian dinosaurs are known from the Jurassic and Cretaceous. The last members of the group died out at the Cretaceous-Tertiary boundary, 65 million years ago. Seen here is a ceratopsian dinosaur trackway. Ceratopsian footprints are very rare. The best examples are in Colorado's Laramie Formation, a nonmarine, coastal plain to deltaic succession of mostly mixed siliciclastic sedimentary rocks - sandstones, siltstones, claystones, and coals. The footprints here consist of convex bulges on the basal surfaces of structurally-tilted sandstone beds. The ichnospecies Ceratopsipes goldenensis was named based on footprints at this locality. The trackmaker was very likely Triceratops, the # 1 most famous ceratopsian dinosaur. From on-site signage: Triceratops Tracks Several tracks of Triceratops, or a closely related horned dinosaur were first discovered in this area and named Ceratopsipes goldenensis (meaning tracks of a horned dinosaur from Golden). By happy coincidence, the first Triceratops known to science also comes from the greater Denver area near 13th Avenue and Federal Blvd. Growing to a length of almost 25 feet, Triceratops and other members of the horned dinosaur family were herbivorous animals that roamed in herds. Their trademark horns and frills that covered their necks probably served for defense. A replica Triceratops skull is on display in the clubhouse at the Fossil Trace Golf Club. These tracks (identified by small signs) help us understand that Triceratops walked with a narrow gait and erect front limbs than with a wide, sprawling gait as previously depicted. In 1887, the first Triceratops bones known to science were also discovered locally at a site near 13th Avenue and Federal Boulevard in Denver. Nearby one may see many other traces of life such as burrows, probably made by invertebrates and impressions of plant debris. Note that you are looking at all tracks and traces from the underside - in negative aspect - what one might call a worm’s eye view. All of these trace fossils indicate that the Golden area once had a warm, temperate to subtropical climate. Classification: Animalia, Chordata, Vertebrata, Reptilia, Archosauria, Dinosauria, Ornithischia, Marginocephalia, Ceratopsia, Ceratopsidae Stratigraphy: Laramie Formation, Maastrichtian Stage, upper Upper Cretaceous Locality: outcrop along Triceratops Trail, Parfet Prehistoric Preserve, southern side of the town of Golden, Colorado, USA (~vicinity of 39° 44' 35.24" North latitude, 105° 13’ 09.69" West longitude) Some info. from: Lockley & Hunt (1995) - Ceratopsid tracks and associated ichnofauna from the Laramie Formation (Upper Cretaceous: Maastrichtian) of Colorado. Journal of Vertebrate Paleontology 15: 592-614.

Malefica is a hadrosaurid dinosaur from the Late Cretaceous of Texas in the United States. Like other hadrosaurs, Malefica was herbivorous, processing plant matter with their broad beaks and battery of teeth in the back of the mouth. It could grow to around 6 m in length, and weighed about 1 t. The discovery of Malefica helped to understand the distribution of hadrosaurs in Cretaceous North America, as well as evolutionary lineages between basal hadrosaurs and the more derived saurolophids.

Theiophytalia kerri Brill & Carpenter, 2006 - ornithopod dinosaur skull from the Cretaceous of Colorado, USA. (YPM 1887, public display, Garden of the Gods visitor center, Colorado Springs, Colorado, USA) This skull is the holotype and only known specimen of an entire genus of ornithopod dinosaurs, Theiophytalia. Ornithopods were herbivorous dinosaurs. From exhibit signage: A Brand New Dinosaur Species Theiophytalia kerri What we know about the dinosaur fossil - so far: It is the only Theiophytalia kerri fossil known to exist in the world. It is a brand new genus and species of dinosaur. Theiophytalia kerri means "belonging to the Garden of the Gods". "Theios" is a Greek word that means "belonging to the gods" and "phytalia" means "garden". "kerri" honors James Hutchinson Kerr (pronounced "Care"), who discovered the dinosaur fossil. Theiophytalia was a medium-sized dinosaur, measuring about 30 feet from head to tail. It was found in 1878 in the Garden of the Gods in the lower Lytle Member of the Purgatoire Rock Formation of the Dakota Group. The dinosaur fossil skull is from the Aptian-Albian Age of the Cretaceous Ear, 125 - 100 million years old. Look closely at the fossil skull. Where are the teeth located? You can see the teeth in the back of the jaw. There are no teeth in the front of the dinosaur's beak-like mouth. This is evidence that the Theiophytalia was a plant eater. It could nip and tear plants, then grind them between its tightly-packed back teeth, similar to plant-eaters of today. Timeline: Dinosaur Fossil Discovered, then Forgotten 1878 - James Kerr, geology professor at Colorado College, finds a fossil skull "in one of the ridges east of the red rocks of the Garden of the Gods." 1886 - O.C. Marsh, famous 1800s dinosaur collector from Yale University, obtains the fossil skull from James Kerr, identifies it as a Camptosaurus dinosaur, and sends the fossil to the Yale Peabody Museum in New Haven, Connecticut. 1886 - 1995 - While the dinosaur fossil skull safely rests in the Yale Museum for many decades, knowledge of its existence is forgotten in Colorado Springs. Rediscovery - 117 years later 1994 - Colorado Springs City park staff research new exhibits for the Garden of the Gods Visitor and Nature Center, set to open in 1995. They meet with Doctor Kirk Johnson, curator of paleontology at the Denver Museum of Nature & Science. 1995 - Kirk Johnson refers the park staff to his museum colleague Doctor Ken Carpenter, expert dinosaur scientist. Doctor Carpenter remembers seeing in his files "something about a dinosaur fossil found in Garden of the Gods" and mails the following article to park staff. Camptosaurus amplus No. 1887, Yale Museum, consisting of portions of the skull and lower jaw. It was collected from deposits in the Garden of the Gods, Colorado Springs, Colorado. With this specimen was found the following note in Professor O.C. Marsh's handwriting, "Part of this animal and various Sauropoda bones were taken out by Professor Kerr in 1878." A Case of Mistaken Identity Reveals a Brand New Dinosaur! 1996 - Kirk Johnson (a Yale alumnus) secures permission to hand-carry the Camptosaurus fossil from the Yale Peabody Museum to Denver so that Ken Carpenter can make a cast (a precise replica) of the fossil. Doctor Carpenter notices irregularities in the Camptosaurus fossil and decides to re-examine the fossil when his schedule permits. 1997 - The Camptosaurus fossil replica is given to the City of Colorado Springs and is exhibited at the Garden of the Gods Visitor and Nature Center. 2006 - Doctor Carpenter and his associate Kathleen Brill reassess the fossil skull and note that it differs from other Camptosaurus skulls in several significant ways, such as the narrower mouth and snout, and the position of the nasal openings, and the bony structures over the eyes. Also, microscopic identification of the rock matrix clinging to the fossil, and research of archival maps, reveal that the fossil skull was actually found in the lower Dakota Rock Formation, not the Morrison Formation as originally reported in the 1800s. The skull is from a dinosaur that lived in the Cretaceous Ear and can't be a Jurassic Era Camptosaurus. Doctor Carpenter's exacting research reveals that the dinosaur skull is a brand new genus and species of dinosaur! He names it Theiophytalia kerri. 2008 - The Theiophytalia kerri is proudly re-exhibited at the Garden of the Gods Visitor and Nature Center. Classification: Animalia, Chordata, Vertebrata, Dinosauria, Ornithischia, Ornithopoda Stratigraphy: lower Lytle Member, Purgatoire Formation, Dakota Group, Aptian to Albian Stages, upper Lower Cretaceous Locality: Garden of the Gods, Colorado Springs, Colorado, USA See info. at: en.wikipedia.org/wiki/Theiophytalia and en.wikipedia.org/wiki/Ornithopoda

Blue Dinosaur Royal Ontario Museum

Blue Dinosaur Royal Ontario Museum

Blue Dinosaur Royal Ontario Museum

Blue Dinosaur Royal Ontario Museum

Palaeogeographic distribution of late Early and early Late Cretaceous pterosaur assemblages. Taxonomic composition of assemblages shown on Fig. 1. Palaeogeography based on Smith et al. 1994. Abbreviations: 1. Cambridge Greensand, England: 2. Lower Chalk, England: 3. Züümbayan Svita, Khuren-Dukh, Mongolia: 4. Lysaya Gora, Saratov, Russia: 5. Kem Kem red beds, Morocco: 6. Paw Paw Formation, Texas, USA: 7. Lagarcito Formation, San Luis, Argentina: 8. Santana and Crato Formations, Ceara, Brazil: 9. Toolebuc Formation, Queensland, Australia.

Precious opal from Australia. (public display, Denver Museum of Nature & Science, Denver, Colorado, USA) A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates. The silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4. Opal is hydrous silica (SiO2·nH2O). Technically, opal is not a mineral because it lacks a crystalline structure. Opal is supposed to be called a mineraloid. Opal is made up of extremely tiny spheres (colloids - <a href="https://www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg" rel="nofollow">www.uwgb.edu/dutchs/acstalks/acscolor/OPALSPHR.jpg</a>) that can be seen with a scanning electron microscope (SEM). Gem-quality opal, or precious opal, has a wonderful rainbow play of colors (opalescence). This play of color is the result of light being diffracted by planes of voids between large areas of regularly packed, same-sized opal colloids. Different opalescent colors are produced by colloids of differing sizes. If individual colloids are larger than 140 x 10-6 mm in size, purple & blue & green colors are produced. Once colloids get as large as about 240 x 10-6 mm, red color is seen (Carr et al., 1979). Not all opals have the famous play of colors, however. Common opal has a wax-like luster & is often milky whitish with no visible color play at all. Opal is moderately hard (H = 5 to 6), has a white streak, and has conchoidal fracture. Several groups of organisms make skeletons of opaline silica, for example hexactinellid sponges, diatoms, radiolarians, silicoflagellates, and ebridians. Some organisms incorporate opal into their tissues, for example horsetails/scouring rushes and sawgrass. Sometimes, fossils are preserved in opal or precious opal. The precious opal shown above is surrounded by silicified claystone. The rock is from the Griman Creek Formation, a Cretaceous-aged succession of nonmarine, fine-grained and coarse-grained siliciclastic sedimentary rocks. Stratigraphy: Griman Creek Formation, Albian Stage, upper Lower Cretaceous Locality: Coocoran Opal Field, west-southwest of Coocoran Lake, northern New South Wales, eastern Australia Photo gallery of opal: <a href="http://www.mindat.org/gallery.php?min=3004" rel="nofollow">www.mindat.org/gallery.php?min=3004</a> References cited: Carr et al. (1979) - Andamooka opal fields: the geology of the precious stones field and the results of the subsidised mining program. Geological Survey of South Australia Department of Mines and Energy Report of Investigations 51. 68 pp.