Morrison Formation 1149977 225706558 2008-07-15T00:25:55Z J. Spencer 568400 /* Site comparisons */ tweaks [[Image:Green River UT 2005-10-14 2104.jpg|thumb|250px|The distinctive banding of the Morrison Formation, a group of rock layers that occur throughout [[Dinosaur National Monument]] and the source of fossils like those found at the Dinosaur Quarry.]] The '''Morrison Formation''' is a distinctive sequence of Late [[Jurassic]] [[sedimentary rock]] that is found in the western United States and Canada, which has been the most fertile source of [[dinosaur]] fossils in [[North America]]. It is composed of [[mudstone]], [[sandstone]], [[siltstone]] and [[limestone]] and is light grey, greenish gray, or red. Most of the [[fossil]]s occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the [[Jurassic]] period. It is centered in [[Wyoming]] and [[Colorado]], with outcrops in [[Montana]], [[North Dakota]], [[South Dakota]], [[Nebraska]], [[Kansas]], the panhandles of [[Oklahoma]] and [[Texas]], [[New Mexico]], [[Arizona]], [[Utah]], and [[Idaho]]. It covers an area of 1.5 million square [[kilometre|km]] (600,000 square [[mile]]s), although only a tiny fraction is exposed and accessible to [[geologist]]s and [[paleontologist]]s. Over 75% is still buried under the prairie to the east and much of the rest was destroyed by erosion as the [[Rocky Mountains]] rose to the west. It was named after [[Morrison, Colorado]], where the first fossils were discovered by [[Arthur Lakes]] in [[1877]]. That same year, it became the center of the [[Bone Wars]], a fossil-collecting rivalry between early paleontologists [[Othniel Charles Marsh]] and [[Edward Drinker Cope]]. [[Image:MorrisonType-1.JPG|thumb|250px|Morrison at the type locality (the location that defines the formation) at Dinosaur Ridge, west of Denver, Colorado.]] [[Image:MorrisonType-2.JPG|250px|thumb|Close-up of the Morrison at the type locality.]] In [[Colorado]], [[New Mexico]], and [[Utah]], the Morrison Formation was a major source of [[uranium]] ore. (See [[Uranium mining in the United States]].) == Geologic History == According to [[radiometric dating]], the Morrison Formation dates from 156.3&nbsp;±&nbsp;2&nbsp;million years old ([[Mega-annum|Ma]]) at its base,<ref name=TCR06>{{cite journal |last=Trujillo |first=K.C. |coauthors=Chamberlain, K.R.; and Strickland, A. |year=2006 |title=Oxfordian U/Pb ages from SHRIMP analysis for the Upper Jurassic Morrison Formation of southeastern Wyoming with implications for biostratigraphic correlations |journal=Geological Society of America Abstracts with Programs |volume=38 |issue=6 |pages=7}}</ref> to 146.8&nbsp;±&nbsp;1&nbsp;million years old at the top,<ref name=SAB98>{{cite book |last=Bilbey |first=S.A. |year=1998 |chapter=Cleveland-Lloyd Dinosaur Quarry - age, stratigraphy and depositional environments |pages= 87-120 |title=The Morrison Formation: An Interdisciplinary Study |editors=Carpenter, K.; Chure, D.; and Kirkland, J.I. (eds.) |series=Modern Geology '''22''' |publisher=Taylor and Francis Group |issn=0026-7775}}</ref> which places it in the latest [[Oxfordian stage|Oxfordian]], [[Kimmeridgian]], and early [[Tithonian]] [[faunal stages|stages]] of the late Jurassic. This is similar in age to the [[Solnhofen limestone|Solnhofen Limestone]] Formation in [[Germany]] and the [[Tendaguru|Tendaguru Formation]] in [[Tanzania]]. Throughout the western [[USA]], it variously overlies the Middle Jurassic Summerville, Sundance, Bell Ranch, Wanakah, and Stump Formations. At the time, the supercontinent of [[Laurasia]] had recently split into the continents of [[North America]] and [[Eurasia]], although they were still connected by land bridges. North America moved north and was passing through the [[subtropics|subtropical regions]]. The Morrison Basin, which stretched from New Mexico in the south to Saskatchewan in the north, was formed when the precursors to the [[Front Range]] of the Rocky Mountains started pushing up to the west. The deposits from their east-facing [[drainage basin]]s, carried by streams and [[river]]s from the Elko Highlands (along the borders of present-day Nevada and Utah) and deposited in [[swamp]]y lowlands, lakes, river channels and [[floodplain]]s, became the Morrison Formation. In the north, the [[Sundance Sea]], an extension of the [[Arctic Ocean]], stretched through [[Canada]] down to the [[United States]]. [[Coal]] is found in the Morrison Formation of Montana, which means that the northern part of the formation, along the shores of the sea, was wet and swampy, with more vegetation.<!--more than what?--> [[Eolian]], or wind-deposited sandstones are found in the southwestern part, which indicates it was much more arid &mdash; a [[desert]], with sand [[dune]]s. In the [[Colorado Plateau]] region, the Morrison Formation is further broken into four sub-divisions, or ''members''. From the oldest to the most recent, they are: [[Image:Allosaurus-fossilized skull.jpeg|thumb|right|250px|DINO 11541, an ''[[Allosaurus]]'' skull from the Salt Wash Member of the Morrison Formation.]] [[Image:Saltwash Tidwell.JPG|thumb|left|Reddish mudstones of the Tidwell Member underlying the whitish sandstones of the Saltwash Member, south of Cisco, Utah.]] [[Image:BrushyBasin.JPG|thumb|left|Brushy Basin Member on the Colorado Plateau]] [[Image:Popcorn Texture.JPG|thumb|left|"Popcorn" texture due to [[bentonite]], formed from volcanic ash, characterizes the Brushy Basin Member.]] # '''Windy Hill Member:''' The oldest member. At the time, the Morrison basin was characterized by shallow marine and tidal flat deposition along the southern shore of the [[Sundance Sea]]. # '''Tidwell Member:''' The [[Sundance Sea]] receded to Wyoming during this member and was replaced by lakes and [[mudflat]]s. # '''Salt Wash Member:''' The first purely terrestrial member. The basin was a semi-arid [[alluvial plain]], with seasonal mudflats. # '''Brushy Basin Member:''' Much finer-grained than the Salt Wash Member, the Brushy Basin Member is dominated by mudstone rich in volcanic ash. Rivers flowed from the west into a basin that contained a giant, saline alkaline lake called [[Lake T'oo'dichi']] and extensive wetlands that were located just west of the modern [[Uncompaghre River|Uncompaghre plateau]]. Deposition in the Morrison Formation ended about 147 Ma. The latest Morrison strata are followed by a thirty-million year [[unconformity (geology)|gap in the geologic record]]. The overlying units are the Lower [[Cretaceous]] Cedar Mountain, Burro Canyon, Lytle, and Cloverly Formations. <!-- Comment --> == Fossil finds == Though many of the Morrission Formation fossils are fragmentary, they are sufficient to provide a good picture of the flora and fauna in the Morrison Basin during the Kimmeridgian. Overall, the [[paleoclimate|climate]] was dry, similar to a [[savanna]] but, since there were no [[angiosperm]]s ([[grass]]es, [[flower]]s, and some [[trees]]), the flora was quite different. [[Conifers]], the dominant plants of the time, were to be found with [[ginkgo]]s, [[cycad]]s, [[tree fern]]s, and [[Juncaceae|horsetail rushes]]. Much of the fossilized vegetation was [[riparian]], living along the river flood plains. [[Insect]]s were very similar to modern [[species]], with [[termite]]s building 30 [[metre|m]] (100 [[Foot (unit of length)|ft]].) tall nests. Along the rivers, there were [[fish]], [[frog]]s, [[salamander]]s, [[lizard]]s, [[crocodile]]s, [[turtle]]s, [[pterosaur]]s, [[crayfish]], [[clam]]s, and [[monotreme]]s ([[prototheria]]n [[mammal]]s, the largest of which was about the size of a [[rat]]). The [[dinosaur]]s were most likely riparian, as well. Hundreds of dinosaur fossils have been discovered, such as ''[[Camptosaurus]]'', ''[[Ornitholestes]]'', several [[Stegosauria|stegosaurs]] comprising at least two species of ''[[Stegosaurus]]'' and the slightly older ''[[Hesperosaurus]]'', and the early [[Ankylosauria|ankylosaurs]], ''[[Mymoorapelta]]'' and ''[[Gargoyleosaurus]]'', most notably a very broad range of [[sauropod]]s (the giants of the [[Mesozoic]] era). Since at least some of species are known to have nested in the area (''Camptosaurus'' [[embryo]]es have been discovered), there are indications that it was a good [[natural environment|environment]] for dinosaurs and not just home to migratory, seasonal populations. Sauropods that have been discovered include the ''[[Diplodocus]]'' (most famously, the first nearly-complete specimen of ''D. carnegiei'', which is now exhibited at the [[Carnegie Museum of Natural History]], in Pittsburgh, Pennsylvania), ''[[Camarasaurus]]'' (the most commonly found sauropod), ''[[Brachiosaurus]]'', ''[[Apatosaurus]]'' (also wrongly known as ''[[Apatosaurus|Brontosaurus]]''), ''[[Barosaurus]]'', the uncommon ''[[Haplocanthosaurus]]'' and the ''[[Seismosaurus]]''. The very diversity of the sauropods has raised some questions about how they could all co-exist. While their body shapes are very similar (long neck, long tail, huge elephant-like body), they are assumed to have had very different feeding strategies, in order for all to have existed in the same time frame and similar environment. Roughly three quarters of all ''[[Allosaurus]]'' fossils known have also been recovered from the Morrison Formation. The total is more than sixty partial and nearly-complete skeletons, including the first one ever unearthed (the [[holotype]] specimen). == Sites and quarries == Locations where significant Morrison Formation fossil discoveries have been made include: [[Image:Dinosaur National Monument-inside the Dinosaur Quarry building.jpeg|thumb|right|250px|Workers inside the Dinosaur Quarry building, at the [[Dinosaur National Monument]].]] * '''Bone Cabin, Wyoming''' * '''[[Garden Park, Colorado]]:''' One of the three major sites excavated by the paleontologists Othniel Charles Marsh and Edward Drinker Cope during the Bone Wars in 1877, though most of the specimens were too incomplete to classify (''nomina dubia''). In 1992, a specimen of ''Stegosaurus stenops'' was discovered with its [[Armour (zoology)|armor]] still in place, which confirmed that the dinosaur had two rows of plates on its back. * '''Cleveland-Lloyd Quarry, Utah:''' First excavated by Lee Stokes in 1937. In the Jurassic, the quarry was a mudhole where several enormous sauropods got stuck and apparently caused a feeding frenzy that lured and trapped many carnivorous dinosaurs. Most of the allosaurs are from this site, as well as the unique ''[[Stokesosaurus]]'' and ''[[Marshosaurus]]''. * '''[[Como Bluff]], Wyoming:''' One of the most renowned fossil sites in North America. It was first worked by Cope and particularly Marsh in 1877 and has been the source of many different sauropods and non-dinosaur species. The Cloverly Formation from the Cretaceous and some [[Triassic]] strata are also exposed at this location. * '''[[Dinosaur National Monument]], Utah''' * '''Dry Mesa Quarry, Colorado:''' A wide variety of fauna, as well as the most diverse set of dinosaurs from any Morrison Formation quarry. The first dig was in 1972, by the [[Brigham Young University]]. Unique specimens include the longest dinosaur known, the ''[[Supersaurus]]'', the [[wiktionary:chimera|chimeric]] ''[[Ultrasauros]]'', and the largest [[carnivore]] on the continent, the ''[[Torvosaurus]]''. *'''Fruita Paleontological Resource Area:''' Badlands sites located south of Fruita, Colorado, were actively worked by George Callison from the University of California, Los Angeles. Numerous specimens of mammals, lizards, and crocodiles were found. Most recently, ''[[Fruitafossor windscheffelia]]'' was described from the area. [[Image:FruitaPaleo.JPG|thumb|250px|Fruita Paleontological Resource Area. One of the sites is denoted by the arrow.]] ==Vertebrate fauna== (mostly from Foster [2003], with additional material in the mammal section after [http://home.arcor.de/ktdykes/dryolest.htm]; the higher-level classifications will vary as new finds are made. Only described taxa are included, so several ''[[nomen nudum|Nomina nuda]]'' and undescribed taxa are left out) ===Fish=== Both [[ray-finned fish]] ([[Actinopterygii]]) and [[lobe-finned fish]] ([[Sarcopterygii]]) were present. Ray-finned fish included ''[[Hulettia|Hulettia hawesi]]'', ''[[Morrolepis|Morrolepis schaefferi]]'', and unidentified actinopterygian remains, mostly from [[Bowfin|amiid]]s (bowfins). The lobe-finned fish present were [[lungfish]] ([[Dipnoi]]) of the [[genus]] ''[[Ceratodus]]'', including the common ''Ceratodus guentheri'', ''C. fossanovum'', and ''C. robustus''. ===Amphibians=== [[Amphibian]]s of the Morrison Formation included both [[frog]]s [[Anura]] and [[salamander]]s ([[Caudata]]). Frogs included ''[[Enneabratrachus|Enneabratrachus hechti]]'' and ''[[Rhadinosteus|Rhadinosteus parvus]]''. Salamanders were represented by ''[[Comonecturoides|Comonecturoides marshi]]'' ([[nomen dubium|dubious]]), and unnamed material including two skeletons from Dinosaur National Monument. ===Turtles=== [[Turtle]]s ([[Testudines]]) are very common fossils in the Morrison, due to their bony shells. The most common were ''[[Glyptops|Glyptops plicatus]]'' (very common) and ''[[Dinochelys|Dinochelys whitei]]'' (also common, but not as common as ''Glyptops''). Also present were ''[[Dorsetochelys|Dorsetochelys buzzops]]'' and ''[[Uluops|Uluops uluops]]''. ===Sphenodonts, squamates, and champsosaurs=== A variety of small reptiles were present in the Morrison Formation. [[Sphenodontia]] (the modern [[tuatara]]s) were represented by the common ''[[Opisthias|Opisthias rarus]]'', and ''[[Eilenodon|Eilenodon robustus]]'' and ''[[Theretairus|Theretairus antiquus]]''. [[Lizard]]s ([[Squamata]]) were represented by ''[[Dorsetisaurus]]'' sp., ''[[Paramacellodus]]'' sp., ''[[Parviraptor|Parviraptor gilmorei]]'', ''[[Saurillodon]]'' sp., and ''[[Schilleria|Schilleria utahensis]]''. Champsosaurs ([[Choristodera]]), a type of aquatic reptile superficially similar to crocodiles, were represented by ''[[Cteniogenys|Cteniogenys antiquus]]'', a common genus. ===Crocodylia=== [[Crocodile]]s of a variety of sizes and habitats were common Morrison animals. [[Cursor]]ial [[mesosuchia]]ns, or small terrestrial running crocs, included ''[[Hallopus|Hallopus victor]]'' and "''[[Fruitachampsa|Fruitachampsa callisoni]]''". More [[derived]] crocodilians included ''[[Goniopholis|Goniopholis felix]]'' (common), ''G. gilmorei'', ''G. lucasi'', ''G. stovalli'', ''[[Hoplosuchus|Hoplosuchus kayi]]'', and ''[[Macelognathus|Macelognathus vagans]]''. ===Pterosaurs=== [[Pterosaur]]s, or flying reptiles, are very uncommon fossils in the Morrison, due to their fragility. Several types are known, from both [[Rhamphorhynchoidea|rhamphorhynchoids]] (long-tailed pterosaurs) and [[Pterodactyloidea|Pterodactyloids]] (short-tailed pterosaurs). Rhamphorhynchoids included ''[[Comodactylus|Comodactylus ostromi]]'' and ''[[Harpactognathus|Harpactognathus gentryii]]''. Pterodactyloids included ''[[Dermodactylus|Dermodactylus montanus]]'', ''[[Kepodactylus|Kepodactylus inseperatus]]'', ''[[Laopteryx|Laopteryx priscus]]'', and ''[[Mesadactylus|Mesadactylus ornithosphyos]]''. ===Theropod dinosaurs=== [[Theropod]] [[dinosaur]]s, the [[carnivorous]] dinosaurs, came in several different types. The less [[derived]] types, the [[Ceratosauria|ceratosaurs]] and [[Megalosauridae|megalosaurids]], included ''[[Ceratosaurus|Ceratosaurus nasicornis]]'', ''C. dentisulcatus'', ''C. magnicornis'', ''[[Elaphrosaurus]]'' sp., and the megalosaur ''[[Torvosaurus|Torvosaurus tanneri]]'' (?including ''[[Edmarka|Edmarka rex]]''). [[Allosauridae|Allosaurids]] included the common ''[[Allosaurus|Allosaurus fragilis]]'' (including ''[[Epanterias|Epanterias amplexus]]''), ''A.'' new species, ''[[Antrodemus|Antrodemus valens]]'', and giant ''[[Saurophaganax|Saurophaganax maximus]]''. [[Coelurosauria|Coelurosaurs]], more derived types more closely related to birds, included ''[[Coelurus|Coelurus fragilis]]'', ''[[Ornitholestes|Ornitholestes hermanni]]'', ''[[Tanycolagreus|Tanycolagreus topwilsoni]]'', the possible [[Troodontidae|troodontid]] ''[[Koparion|Koparion douglassi]]'', and the definite [[troodontid]] [[WDC DML 001]]. There was also the possible [[Tyrannosauroidea|early tyrannosaur relative]] ''[[Stokesosaurus clevelandi]]''. ''[[Marshosaurus|Marshosaurus bicentesimus]]'' was a medium-sized theropod of uncertain type that may have been related to the allosaurids. ===Sauropod dinosaurs=== [[Sauropoda|Sauropods]], the giant long-necked long-tailed four-legged [[herbivorous]] dinosaurs, are among the most common and famous Morrison fossils. A few have uncertain relationships, like [[Apatosaurus|"Apatosaurus" ''minimus'']] (possibly an early [[titanosaur]]) and ''[[Haplocanthosaurus]]''. Sauropods including ''[[Haplocanthosaurus|Haplocanthosaurus priscus]]'', ''H. delfsi'', and the [[Diplodocidae|diplodocids]] ''[[Dystrophaeus]]'' and ''[[Eobrontosaurus]]'' appeared in the early stages of the Morrison. The middle stages were dominated by familiar forms such as the [[Giraffe]]-like ''[[Brachiosaurus|Brachiosaurus altithorax]]'', which were uncommon, but related [[Camarasauridae|camarasaurids]], like ''[[Camarasaurus|Camarasaurus supremus]]'', ''C. grandis'', ''C. lentus'', and ''C. lewisi'', were very common. Also common were long, low [[Diplodocidae|diplodocids]], like ''[[Apatosaurus|Apatosaurus ajax]]'', ''A. excelsus'' (formerly "Brontosaurus"), ''A. louisae'', ''A. parvus'', ''[[Atlantosaurus|Atlantosaurus montanus]]'', ''[[Barosaurus|Barosaurus lentus]]'', ''[[Diplodocus|Diplodocus longus]]'', ''D. carnegii'', "D." ''hayi'', "D." ''lacustris'', ''[[Dyslocosaurus|Dyslocosaurus polyonychius]]''. By the late Morrison, gigantic diplodocids (or likely diplodocids) had appeared, including ''Diplodocus hallorum'' (formerly ''Seismosaurus''), ''[[Supersaurus|Supersaurus vivianae]]'', ''[[Amphicoelias|Amphicoelias altus]]'', and the largest of all, ''A. fragilimus''. Smaller sauropods, such as ''[[Suuwassea|Suuwassea emiliae]]'' from [[Montana]], tend to be found in the northern reaches of the Morrison, near the shores of the ancient [[Sundance Sea]], suggesting ecological niches favoring smaller body size there compared with the giants found further south.<ref name="harris&dodson2004">Harris, J.D. and Dodson, P. (2004). "A new diplodocoid sauropod dinosaur from the Upper Jurassic Morrison Formation of Montana, USA." ''Acta Palaeontologica Polonica'', '''49'''(2): 197–210.</ref> ===Ornithischian ("bird-hipped") dinosaurs=== The herbivorous [[ornithischian]] dinosaurs were diverse but not as common as sauropods in the Morrison. Unclassified members include the "Fruita ''[[Echinodon]]''", a possible [[Heterodontosauridae|heterodontosaurid]], and the dubious ''[[Tichosteus|Tichosteus lucasanus]]'' and ''T. aequifacies''. Plate-backed [[Stegosauridae|stegosaurids]] included ''[[Hesperosaurus|Hesperosaurus mjosi]]'', ''[[Hypsirophus|Hypsirophus discursus]]'', ''[[Stegosaurus|Stegosaurus armatus]]'' (?including ''S. ungulatus''), ''S. stenops'', and "S." ''longispinus''. [[Ankylosauria|Armored dinosaurs]] that weren't stegosaurs were unknown in the formation until the 1990s. Two have been named: ''[[Gargoyleosaurus|Gargoyleosaurus parkpinorum]]'' and ''[[Mymoorapelta|Mymoorapelta maysi]]''. [[Ornithopoda|Ornithopods]], bipedal herbivores, came in several types. Small "[[Hypsilophodontidae|hypsilophodonts]]" included ''[[Drinker nisti]]'', ''[[Laosaurus celer]]'', "L." ''gracilis'', ''[[Nanosaurus|Nanosaurus agilis]]'', ''[[Othnielia|Othnielia rex]]'', and ''[[Othnielosaurus|Othnielosaurus consors]]''. Larger but similar-looking [[Dryosauridae|dryosaurids]] were represented by ''[[Dryosaurus|Dryosaurus altus]]'' and the camptosaurid ''[[Camptosaurus]] aphanoecetes'', which is currently known only from Dinosaur National Monument. Still larger was the more common ''[[Camptosaurus|Camptosaurus dispar]]'', probably including ''[[Brachyrophus|Brachyrophus altarkansanus]]'' and ''[[Symphyrophus|Symphyrophus musculosus]]''. Dryosaurids and [[Camptosauridae|camptosaurids]] were early [[iguanodont]]s, a group that would later spawn the [[hadrosaur|duck-billed dinosaurs]]. ===Mammals=== Many types of early [[Mammalia|mammals]] are known from the Morrison; almost all of them were small, [[rodent]]-like animals. Unclassified types include the digger ''[[Fruitafossor|Fruitafossor windscheffelia]]''. [[Docodonta|Docodonts]] included the common genus ''[[Docodon]]'', represented by ''D. victor'', ''D. striatus'', and ''D. superbus'', and ''[[Peraiocynodon]]'' sp. [[Multituberculata|Multituberculates]], a common type of early mammal, were represented by ''[[Ctenacodon|Ctenacodon serratus]]'', ''C. laticeps'', ''C. scindens'', "C." ''brentbaatar'', ''[[Glirodon|Glirodon grandis]]'', ''[[Psalodon|Psalodon fortis]]'', ''?P. marshi'', ''P. potens'', and ''[[Zofiabaatar|Zofiabaatar pulcher]]''. [[Triconodonta|Triconodonts]] present included ''[[Aploconodon|Aploconodon comoensis]]'', ''[[Conodon|Conodon gidleyi]]'' (AKA ''Phascolodon'' and ''Phascolotheridium''), ''[[Priacodon|Priacodon ferox]]'', ''P. fruitaensis'', ''P. gradaevus'', ''P. lulli'', ''P. robustus'', ''[[Triconolestes|Triconolestes curvicuspis]]'', and ''[[Trioracodon|Trioracodon bisulcus]]''. [[Symmetrodonta|Symmetrodonts]] were represented by ''[[Amphidon|Amphidon superstes]]'', ''[[Eurylambda|Eurylambda aequicrurius]]'' (probably ''Tinodon''), and ''[[Tinodon|Tinodon bellus]]'' (including ''T. lepidus''). Finally, two families of [[Dryolestoidea]] were present: [[Paurodontidae]], including ''[[Araeodon|Araeodon intermissus]]'', ''[[Archaeotrigon|Archaeotrigon brevimaxillus]]'', ''A. distgamus'', ''[[Comotherium|Comotherium richi]]'', ''[[Euthlastus|Euthlastus cordiformis]]'', ''[[Foxraptor|Foxraptor atrox]]'', ''[[Paurodon|Paurodon valens]]'', ''[[Pelicopsis|Pelicopsis dubius]]'', and ''[[Tathiodon|Tathiodon agilis]]''; and [[Dryolestidae]], including ''[[Amblotherium|Amblotherium gracilis]]'', ''[[Dryolestes|Dryolestes obtusus]]'' (common genus), ''D. priscus'', ''D. vorax'', ''[[Laolestes|Laolestes eminens]]'', ''L. grandis'', and ''[[Miccylotyrans|Miccylotyrans minimus]]''. ==Site comparisons== The Morrison Formation is comparable to the [[Tendaguru]] beds in Tanzania and [[Lourinhã Formation]] in Portugal. In age it is also comparable with the [[Solnhofen Limestone]] in Germany. == See also == * [[List of fossil sites]] ''(with link directory)'' ==References== {{reflist}} == External links and references == * [http://www.mnhm.org/ Morrison Natural History Museum] home page. * ''[http://rainbow.ldgo.columbia.edu/courses/v1001/morisson14.html Dinosaurs and the History of Life]'', Columbia University lecture on the Morrison Formation. * [http://www.nps.gov/dino/morrison.htm Geology of the (Dinosaur National Monument) Quarry], from the National Park Service. * ''[http://www.isgs.uiuc.edu/dinos/de_4/5ca00c3.htm The Morrison Formation]'', from the Dinosaur Encyclopedia, including data on the major sites. *[http://paleodb.org/cgi-bin/bridge.pl?action=displayCollectionDetails&collection_no=13275 Paleobiology Database: Dalton Well Dinosaur Track Site (Morrison Formation): Late/Upper Jurassic, Utah] *[http://paleodb.org/cgi-bin/bridge.pl?action=displayCollectionDetails&collection_no=13277 Paleobiology Database: Black Ridge Dinosaur Track Site (Morrison Formation): Late/Upper Jurassic, Colorado] *[http://home.arcor.de/ktdykes/dryolest.htm Catalogue of Morrison mammals (bottom of the page)] ==Other References== *Foster, J.R. 2003. ''Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A.'' Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. Bulletin 23. *Mateus, O. 2006. Late Jurassic dinosaurs from the Morrison Formation, the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania): a comparison. in Foster, J.R. and Lucas, S. G. R.M., eds., 2006, Paleontology and Geology of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural History and Science Bulletin 36: 223-231. 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